Take a look at the passage again:
Ever since Andre peeked at Melissa's paper during the biology exam.
Guilt has consumed him. Even the blueberries
floating in his cereal bowl seem like the accusing eyes of Dr. Gregory,
his biology instructor.
You chose the second part, Guilt has consumed him. This part has a main clause: Guilt is the subject; has consumed is the verb. A fragment will not have a main clause.
Go back to the passage to try again.