Which of the following sentences uses the semicolon correctly? Group of answer choices

a. Students sometimes forget to study; because there are more interesting things to do, this makes it harder for them to make good grades.

b. Students sometimes forget to study because there are more interesting things to do; this makes it harder for them to make good grades.

c. Students: forget to study sometimes because there are more interesting things to do, this makes it harder for them to make good grades.

d. Students sometimes forget to study because there are more interesting things to do, this makes it harder; for them to make good grades.