The correct answer is C. Machiavelli uses logical evidence to assert that it is acceptable for new princes to use cruelty.
Indeed, the author is using the common knowledge of his time and that includes a literary quote from the Latin Poet Virgil, about the myth of Dido, which does not really have historical value since according to most historians she did not exist. His reasoning is not based on a fact but rather on an “expert opinion” based on logical reasoning.