Explanation
A. The amount of documentation from Caligula's reign compared to other Roman emperors does not directly support the modern historians' challenge.
B. The perception of people who lived under Caligula does not directly support the historians' challenge regarding the lack of reliable documentation.
C. (Correct Response) If the outrageous acts attributed to Caligula are very similar to those attributed to other rulers known to be cruel tyrants, it could indicate that these descriptions are formulaic and may not be reliable accounts of Caligula's reign. This supports the modern historians' challenge by suggesting that the accounts of Caligula's behavior could be exaggerated or standard portrayals of tyranny rather than objective history.
D. The belief of the Roman people regarding Caligula's cruelty is not at issue; the challenge is about the objectivity and reliability of the historical documentation.
E. Documentation of modern tyrants is not relevant to the issue of how accurately historical documents portray Caligula.