You will be given a definition of a task first, then some input of the task.
In this task, you are given a context, a subject, a relation, and many options. Based on the context, from the options select the object entity that has the given relation with the subject. Answer with text (not indexes).

Context: An observatory is a location used for observing terrestrial or celestial events. Astronomy, climatology/meteorology, geology, oceanography and volcanology are examples of disciplines for which observatories have been constructed. Historically, observatories were as simple as containing an astronomical sextant (for measuring the distance between stars) or Stonehenge (which has some alignments on astronomical phenomena)., Massachusetts ; officially the Commonwealth of Massachusetts, is the most populous state in the New England region of the northeastern United States. It is bordered by the Atlantic Ocean to the east, the states of Connecticut and Rhode Island to the south, New Hampshire and Vermont to the north, and New York to the west. The state is named for the Massachusett tribe, which once inhabited the area. The capital of Massachusetts and the most populous city in New England is Boston. Over 80% of Massachusetts' population lives in the Greater Boston metropolitan area, a region influential upon American history, academia, and industry. Originally dependent on agriculture, fishing and trade, Massachusetts was transformed into a manufacturing center during the Industrial Revolution. During the 20th century, Massachusetts' economy shifted from manufacturing to services. Modern Massachusetts is a global leader in biotechnology, engineering, higher education, finance, and maritime trade., A crater chain is a line of craters along the surface of an astronomical body. The descriptor term for crater chains is catena (plural catenae), as specified by the International Astronomical Union's rules on planetary nomenclature., Secondary craters are impact craters formed by the ejecta that was thrown out of a larger crater. They sometimes form radial crater chains. In addition, secondary craters are often seen as clusters or rays surrounding primary craters. The study of secondary craters exploded around the mid-twentieth century when researchers studying surface craters to predict the age of planetary bodies realized that secondary craters contaminated the crater statistics of a body's crater count., In geology, a graben is a depressed block of land bordered by parallel faults. "Graben" is German for "ditch" or "trench". The plural form is either graben or grabens., The Massachusetts Institute of Technology (MIT) is a private research university in Cambridge, Massachusetts. Founded in 1861 in response to the increasing industrialization of the United States, MIT adopted a European polytechnic university model and stressed laboratory instruction in applied science and engineering. Researchers worked on computers, radar, and inertial guidance during World War II and the Cold War. Post-war defense research contributed to the rapid expansion of the faculty and campus under James Killian. The current campus opened in 1916 and extends over along the northern bank of the Charles River basin., The United States Air Force (USAF) is the aerial warfare service branch of the United States Armed Forces and one of the seven American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on 18 September 1947 under the National Security Act of 1947. It is the most recent branch of the U.S. military to be formed, and is the largest and one of the world's most technologically advanced air forces. The USAF articulates its core functions as Nuclear Deterrence Operations, Special Operations, Air Superiority, Global Integrated ISR, Space Superiority, Command and Control, Cyberspace Superiority, Personnel Recovery, Global Precision Attack, Building Partnerships, Rapid Global Mobility and Agile Combat Support., Westford is a town in Middlesex County, Massachusetts, United States. The population was 21,951 at the 2010 census., Haystack Observatory is an astronomical observatory owned by Massachusetts Institute of Technology (MIT). It is located in Westford, Massachusetts (USA), approximately northwest of Boston. Haystack was initially built by MIT's Lincoln Laboratory for the United States Air Force and was known as Haystack Microwave Research Facility. Construction began in 1960, and the antenna began operating in 1964. In 1970 the facility was transferred to MIT, which then formed the Northeast Radio Observatory Corporation (NEROC) with a number of other universities to operate the site as the Haystack Observatory. , a total of nine institutions participated in NEROC., Haystack Catena ( Haystack Vallis until March 2013 ) is a catena at 4.7 ° N , 46.2 ° W on Mercury . It superficially resembles a graben but is actually a chain of overlapping secondary craters . It was named after Haystack Observatory ., Geology (from the Ancient Greek , "g", i.e. "earth" and -o, "-logia", i.e. "study of, discourse") is an earth science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which they change. Geology can also refer generally to the study of the solid features of any terrestrial planet (such as the geology of the Moon or Mars)., Subject: haystack catena, Relation: instance_of, Options: (A) air force (B) area (C) armed forces (D) bank (E) campus (F) capital (G) century (H) construction (I) corporation (J) county (K) crater chain (L) distance (M) ditch (N) economy (O) education (P) engineering (Q) england (R) finance (S) force (T) geology (U) graben (V) history (W) institute of technology (X) island (Y) metropolitan (Z) model ([) number (\) observatory (]) planet (^) polytechnic (_) population (`) rapid (a) research (b) revolution (c) river (d) science (e) security (f) service (g) state (h) study (i) technology (j) terrestrial planet (k) town (l) university (m) war
Output:
crater chain