B is the answer.
A would be okay if Margaret wasn't a female name, and they used male pronouns to describe her actions.
C "King" should not be capitalized because it is not a proper noun - meaning it's not the king's name. Again, king is a male title, and they follow up with female pronouns.
D shouldn't say "himselves" but rather "themselves", because it cannot be assumed that every student is a male, and more so, himselves is not a word at all, because "himself" represents an individual male.
