I believe the correct answer would be A. The best correlation to use to measure the relationship between gender and grade point average for a group of college students would be the point-biserial correlation. It is coefficient that is used when a variable is dichotomous or that the variable is part of a whole set. It is used in measuring the direction of the correlation that is present between a dichotomous variable and a continuous variable. From the question, the dichotomous variable would be the grade point average for a group of college students while the other variable is the continuous one.
