The proportion of men among students enrolled in nursing or medical assistant programs has increased over the last several decades. For example, in 1965, less than 1 percent of men between the ages of eighteen and twenty-five were enrolled in a nursing or medical assistant program, while in 1995, 4.5 percent of men between the ages of eighteen and twenty-five were enrolled in these programs.

Which of the following statistics, if available for both 1965 and 1995, would be most helpful in evaluating the truth of the comparison presented above?

a. The percentage of men between the ages of eighteen and twenty-five who were not enrolled in nursing or medical assistant programs.
b. The percentage of men between the ages of eighteen and twenty-five who graduated from nursing and medical assistant programs.
c. The percentage of men who, after attending nursing or medical assistant programs, entered these professions.
d. The percentage of women between the ages of eighteen and twenty-five who were enrolled in nursing or medical assistant programs at these same times.
e. The percentage of high school graduates who went on to pursue higher education.
[spoiler]Source : Kaplan Test1, OA later.Caution : Its a trap question, do it slowly[/spoiler]