$(4$ points$)$ Which of the following comparisons would use a t$-$test comparing two independent groups?

$($Check all that apply$)$:

Fifteen retirees with diagnosed hypertension are assigned a program of diet, exercise, and meditation. A baseline measurement of blood pressure is taken before the program begins and again after $2$ months. Was the program effective in reducing blood pressure of the participants after analyzing the mean blood pressure before the program compared to mean blood pressure after the program?

Comparing average GPA of male undergraduate students vs$.$ average GPA of female undergraduate students

Comparing average age of juniors vs$.$ average age of seniors.