Select the correct number of factors and levels for this study: A researcher would like to test if strategy type affects the time to complete an exam. The researcher assigns 24 student volunteers to...

Select the correct number of factors and levels for this study: A researcher would like to test if strategy type affects the time to complete an exam. The researcher assigns 24 student volunteers to one of the following 3 treatment groups: a group that crams for 12 hours before exam, a group that crams for 3 days before exam, and a group that studies for 1 week before the exam.

a. 3 factors, 1 level

b. 3 factors, 3 levels

c. 1 factor, 3 levels

d. 1 factor, 1 level