This question is fairly straight forward. I approached the question like so:
Premise: Akhenaten soldiers showed him fierce loyalty as documented by the reports written during his time.
Conclusion: because of this (fierce loyalty shown by soldiers) we know that he was loved and highly respected by his subjects.
My two assumptions derived before looking at the answer choices:
Assumption 1: loyalty= love and respect
Assumption 2: soldiers= all his subjects
A-introduce info that conflicts the conclusion-what conflicting info? wrong answer
B-relies on info that is impossible to challenge- just because it is based on information (the soldiers) and books (reports written during Akhenten's reign) that are old does not mean that we cannot challenge the information.
D-ambiguity of the term "ancient"- wrong answer the word was used consistently through out the stimulus.
E-present day standards--what? are you kidding me? wrong
C- correct answer-makes a generalization (Akhenten was well loved and respected) based on his sample (his solders loyalty) that is likely to be unrepresentative (of all his subjects)
This answer choice embodies Assumption 2 from above. This is the method I use for most Assumption questions