What Provides the Best Explanation for Why Steve,who Did Not

What provides the best explanation for why Steve,who did not read the chapter the night before,is overwhelmed by Professor Griffith's lecture on the Civil War,while Mary,who did read the chapter,is not?

A) Mary is able to chunk parts of the lecture because of her prior knowledge.
B) Steve is feeling the effects of retroactive inhibition.
C) The professor's lecture has put too much strain on Steve's short-term memory capacity.
D) Mary is not affected by proactive inhibition.