A researcher with the Department of Education followed a cohort of students who graduated from high school in a certain year, monitoring the progress the students made toward completing a bachelor's degree. One aspect of his research was to determine whether students who first attended community college took longer to attain a bachelor's degree than those who immediately attended and remained at a 4-year institution. The data in the table attached below summarize the results of his study. Complete parts a) through e) below. Click here to view the sample data. Click here to view Student's t-distribution table. a) What is the response variable in this study? What is the explanatory variable? A. The response variable is the use of community college or not. The explanatory variable is the time to graduate. B. The response variable is the number of students. The expl ory variable is the time to graduate. O C. The response variable is the time to graduate. The explanatory variable is the use of community college or not. D. The response variable is the time to graduate. The explanatory variable is the number of students.