The conclusion of the argument is the following:
during those 50 years, monks probably only rarely ate fish even on occasions when meat was forbiddenThe conclusion is supported by the following information:
Under the monastery's dietary rules at the time, there were many occasions on which fish could be eaten but not meat. Yet of the bones in the waste heap, only a small proportion are fish bones.The reasoning of the argument is basically that, because "only a small proportion" of the bones in the waste heap are fish bones, it's probable that the monks rarely ate fish even when eating meat was forbidden.
The correct answer must be an assumption upon which that reasoning depends.
A. Under the monastery's dietary rules, there were no occasions on which monks were not permitted to eat fish.Notice that, even if there WERE occasions on which monks were not permitted to eat fish, the argument would still work because the conclusion is that the monks rarely ate fish, and there being occasions on which monks were not permitted to eat fish is in line with the idea that the monks rarely ate fish.
So, even if this choice is not true, the argument works.
Eliminate.
B. Under the monastery's dietary rules, there were no occasions on which monks were required to eat fish.Notice that even if there WERE occasions on which monks were required to eat fish, the evidence that "only a small proportion" of the bones in the waste heap are fish bones still supports the conclusion that "monks probably only rarely ate fish."
After all, even if the monks were required to eat fish on some occasions, it still appears that they rarely ate fish.
So, the argument does not depend on the assumption that "there were NO occasions on which monks were required to eat fish."
Eliminate.
C. During the fourteenth century there were no readily available supplies of fish in the area near the monastery.The argument uses the fact that "only a small proportion" of the bones in the waste heap are fish bones to support the conclusion that "monks probably only rarely ate fish."
That information supports the conclusion regardless of whether there were readily available supplies of fish in the area near the monastery. After all, even if there were readily available supplies of fish in the area near the monastery, the fact that only a small proportion of the bones in the waste heap are fish bones indicates that the monks rarely ate fish.
Eliminate.
D. The excavated waste area was not widely used by the monastery's neighbors.Notice that the author uses the proportions of bones in the waste heap to determine what the monks ate. In doing so, the author makes the general assumption that the contents of the waste heap accurately indicate what the monks ate.
So, what if the excavated waste area WAS widely used by the monastery's neighbors? In that case, it could be that the contents of the waste heap do not indicate what the monks ate. In other words, it could be that the monks often ate fish but only a small proportion of the bones in the waste heap are fish bones because the neighbors didn't each much fish.
So, the argument depends on the assumption that "the excavated waste area was NOT widely used by the monastery's neighbors.
Keep.
E. During the 50 years, the monks strictly observed the monastery's dietary rules.Regardless of how strictly the monks observed the monastery's dietary rules, the fact that "only a small proportion" of the bones in the waste heap are fish bones supports the conclusion that "monks probably only rarely ate fish."
After all, even if the monks did NOT observe the monastery's dietary rules, the proportions of different types of bones in the waste heap still indicate that they didn't eat fish.
So, this choice is not a necessary assumption.
Eliminate.
The correct answer is