The Following Table Describes the Opinions of the 570 People

The following table describes the opinions of the 570 people that returned a residential life services questionnaire to researchers at a small university. Students were classified by class (freshman, sophomore, junior, or senior) and by their opinion of campus residence quality (high quality, medium quality, or low quality) . Which marginal or conditional distribution would you use to determine the percent of all students who responded that are sophomores?

A) the marginal distribution of class
B) the marginal distribution of opinion of residence quality
C) the conditional distribution of opinion of residence quality, given that class is "sophomore"
D) None of the answer options is correct.