Premise:
1. Archaeologists have found underwater etchings near the jungle city of Manaus, following a drought in the Brazilian Amazon.
2. Previously, archaeologists studying the Amazon believed that the rainforest was too inhospitable to host a major civilization and that the only civilizations in the area were nomadic.
Conclusion:
thousands of years ago the Amazon was home to large civilizations.
The conclusion is based upon the discovery of etching. We have been asked to weaken the conclusion. We have to look for something that tells us that Amazon wasn't home to large civilizations.
(A) Remnants of large established villages with well-trodden roads going by or through them were unearthed near the location of the drawings............................
This strengthens the conclusion.(B) The etchings exhibited an unexpected sophistication for that period, yet they still showed the telltale signs of being of that period........
Not weakening the conclusion(C) Archaeologists proved that a nomadic artist created the etchings and very similar etchings almost 100 miles away................If that is the case then we can't say that there was any civilization. The etchings were created by Nomadic artists. Then the basis of the conclusion becomes weak. This is our answer
(D) The drought that exposed the submerged etchings was the first in that area in more than 2,000 years..................
Not weakening(E) The etchings included a representation of hunters walking across a plain and people building small domiciles..................
Not weakeningIMO OA should be C