Problem: I know that the answer to the question "In 1999, was producing bitumen profitable or uneconomic?" is in "Naturally occurring crude asphalt/bitumen impregnated in sedimentary rock is the prime feed stock for petroleum production from "Oil sands", currently under development in Alberta, Canada. Canada has most of the world's supply of natural asphalt/bitumen, covering 140,000 square kilometres (an area larger than England), giving it the second-largest proven oil reserves in the world. The Athabasca oil sands is the largest asphalt/bitumen deposit in Canada and the only one accessible to surface mining, although recent technological breakthroughs have resulted in deeper deposits becoming producible by in situ methods. Because of oil price increases after 2003, producing bitumen became highly profitable, but as a result of the decline after 2014 it became uneconomic to build new plants again. By 2014, Canadian crude asphalt/bitumen production averaged about 2.3 million barrels (370,000 m3) per day and was projected to rise to 4.4 million barrels (700,000 m3) per day by 2020. The total amount of crude asphalt/bitumen in Alberta which could be extracted is estimated to be about 310 billion barrels (50×10^9 m3), which at a rate of 4,400,000 barrels per day (700,000 m3/d) would last about 200 years.". Can you tell me what it is?

A: uneconomic


Problem: I know that the answer to the question "If I lived in the 8th century, what change would I have seen?" is in "The various Germanic states in the west all had coinages that imitated existing Roman and Byzantine forms. Gold continued to be minted until the end of the 7th century, when it was replaced by silver coins. The basic Frankish silver coin was the denarius or denier, while the Anglo-Saxon version was called a penny. From these areas, the denier or penny spread throughout Europe during the centuries from 700 to 1000. Copper or bronze coins were not struck, nor were gold except in Southern Europe. No silver coins denominated in multiple units were minted.". Can you tell me what it is?

A: Gold continued to be minted until the end of the 7th century, when it was replaced by silver coins


Problem: I know that the answer to the question "Which type of infection presents more overt symptoms, latent or active?" is in "Persistent infections occur because the body is unable to clear the organism after the initial infection. Persistent infections are characterized by the continual presence of the infectious organism, often as latent infection with occasional recurrent relapses of active infection. There are some viruses that can maintain a persistent infection by infecting different cells of the body. Some viruses once acquired never leave the body. A typical example is the herpes virus, which tends to hide in nerves and become reactivated when specific circumstances arise.". Can you tell me what it is?

A: active


Problem: I know that the answer to the question "Of the dams that were damaged in the earthquake, how many were small?" is in "The Zipingpu Hydropower Plant (simplified Chinese: 紫坪铺水库; traditional Chinese: 紫坪鋪水庫) located 20 km east of the epicenter was damaged. A recent inspection indicated that the damage was less severe than initially feared, and it remains structurally stable and safe. The Tulong reservoir upstream is in danger of collapse. About 2,000 troops have been allocated to Zipingpu, trying to release the pressure through spillway. In total, 391 dams, most of them small, were reported damaged by the quake.". Can you tell me what it is?

A:
most