Response questions generally focus on a. specific vocabulary c. key topics b. main events d. all of the above

D is your answer. Response questions generally focus on all of the above: specific vocabulary, key topics, and main events.

voracity is the noun corresponding to the adjective voracious, which means (1) eager to consume a great amount of food, or (2) marked by an insatiable appetite. veracity is far more common than the rare voracity, so the latter is sometimes used in place of the former.