Please answer the following question: Information:  - A system of measurement is a collection of units of measurement and rules relating them to each other. Systems of measurement have historically been important, regulated and defined for the purposes of science and commerce. Systems of measurement in modern use include the metric system, the imperial system, and United States customary units.  - Eurasia is the combined continental landmass of Europe and Asia. The term is a portmanteau of its constituent continents. Located primarily in the Northern and Eastern Hemispheres, it is bordered by the Atlantic Ocean to the west, the Pacific Ocean to the east, the Arctic Ocean to the north, and by Africa, the Mediterranean Sea, and the Indian Ocean to the south. The division between Europe and Asia as two different continents is a historical and cultural construct, with no clear physical separation between them; thus, in some parts of the world, Eurasia is recognized as the largest of five or six continents. In geology, Eurasia is often considered as a single rigid megablock. However, the rigidity of Eurasia is debated based on the paleomagnet data.  - The metric system is an internationally agreed decimal system of measurement. It was originally based on the and the introduced by the French First Republic in 1799, but over the years the definitions of the metre and the kilogram have been refined, and the metric system has been extended to incorporate many more units. Although a number of variants of the metric system emerged in the late nineteenth and early twentieth centuries, the term is now often used as a synonym for "SI" or the "International System of Units"the official system of measurement in almost every country in the world.  - A native system of weights and measures was used in Imperial Russia and after the Russian Revolution , but it was abandoned in 1924 when the Soviet Union adopted the metric system . The Tatar system is very similar to the Russian one , but some names are different . The system existed since ancient Rus ' , but under Peter the Great , the Russian units were redefined relative to the English system . Until Peter the Great the system also used Cyrillic numerals , and only in the 18th century did Peter the Great replace it with the Hindu - Arabic numeral system .  - The International System of Units (; abbreviated as SI) is the modern form of the metric system, and is the most widely used system of measurement. It comprises a coherent system of units of measurement built on seven base units. The system also establishes a set of twenty prefixes to the unit names and unit symbols that may be used when specifying multiples and fractions of the units.  - The metre, or meter (American spelling), (from the Greek noun , "measure") is the base unit of length in the International System of Units (SI). The SI unit symbol is m. The metre is defined as the distance travelled by light in a vacuum in seconds.  - The decimal numeral system (also called base-ten and occasionally called denary) has ten as its base, which, in decimal, is written 10, as is the base in every positional numeral system. It is the numerical base most widely used by modern civilizations.  - The gram (alternative British English spelling: gramme; SI unit symbol: g) (Greek/Latin root "grámma") is a metric system unit of mass.  - In the history of France, the First Republic, officially the French Republic, was founded on 21 September 1792 during the French Revolution. The First Republic lasted until the declaration of the First Empire in 1804 under Napoleon, although the form of the government changed several times. This period was characterized by the fall of the monarchy, the establishment of the National Convention and the Reign of Terror, the Thermidorian Reaction and the founding of the Directory, and, finally, the creation of the Consulate and Napoleon's rise to power.  - The kilogram or kilogramme (SI unit symbol: kg) is the base unit of mass in the International System of Units (SI) (the Metric system) and is defined as being equal to the mass of the "International Prototype of the Kilogram" (IPK, also known as "Le Grand K" or "Big K").  - The Soviet Union, officially the Union of Soviet Socialist Republics (USSR " ) was a socialist state in Eurasia that existed from 1922 to 1991. A union of multiple subnational republics, its government and economy were highly centralized. The Soviet Union was a one-party federation, governed by the Communist Party with Moscow as its capital.  - The erg is a unit of energy and work equal to 10 joules. It originated in the centimetregramsecond (CGS) system of units. It has the symbol "erg". The erg is not an SI unit. Its name is derived from "ergon" () a Greek word meaning "work" or "task".  - Moscow (or ) is the capital and most populous city of Russia, with 12.2 million residents within the city limits and 16.8 million within the urban area. Moscow has the status of a Russian federal city.  - Count (male) or countess (female) is a title in European countries for a noble of varying status, but historically deemed to convey an approximate rank intermediate between the highest and lowest titles of nobility. The word "count" came into English from the French "comte", itself from Latin "comes"in its accusative "comitem"meaning companion, and later companion of the emperor, delegate of the emperor. The adjective form of the word is "". The British and Irish equivalent is an earl (whose wife is a "countess", for lack of an English term). Alternative names for the "count" rank in the nobility structure are used in other countries, such as "Graf" in Germany and "Hakushaku" during the Japanese Imperial era.    After reading the paragraphs above, we are interested in knowing the entity with which 'obsolete russian units of measurement' exhibits the relationship of 'instance of'. Find the answer from the choices below.  Choices: - adjective  - capital  - city  - collection  - communist party  - count  - country  - data  - empire  - energy  - erg  - federation  - geology  - government  - history  - landmass  - mass  - mediterranean sea  - meter  - metre  - metric  - nobility  - number  - numeral system  - ocean  - rank  - republic  - revolution  - sea  - september  - set  - single  - socialist state  - soviet  - state  - status  - structure  - symbol  - synonym  - system  - system of measurement  - term  - title  - union  - unit of energy  - unit of length  - unit of mass  - urban area  - wife  - word  - work
A:
system of measurement