If a Contingency Table Shows the Sex and Classification of Undergraduate

Multiple Choice

If a contingency table shows the sex and classification of undergraduate students (freshman,sophomore,junior,senior) in your statistics class,which of the following is true?

A) The sex of the student is an example of mutually exclusive events.
B) Because yours is an undergraduate class,the events are exhaustive,i.e.,each student must fall in one of the classifications.
C) An example for the intersection of events would be the number of males who are juniors.
D) An example for the union of events would be the number of students who are female or juniors.
E) All of these are true.