PT 5 S1 Q14

A survey of alumni of the class of 1960 at Aurora University yielded puzzling ... ...

Which one of the following most helps account for the apparent contradiction above?
(A) A disproportionately large number of high-ranking alumni responded to the survey.
(B) ...
(C) ...
(D) ...
(E) ...

*This question is included in Practice Set: "Resolve/Explain" Questions, Set 1