I Picked C  can someone please help me !!!!! 
Thanks 
Choose the sentence that is written correctly. 	
A.	If you do not understand why you received a particular score on your assignment you should ask your instructor. 	
B.	If you do not understand why you received a particular score on your assignment.   You should ask your instructor. 
	C.	If you do not understand why you received a particular score on your assignment, you should ask your instructor. 	
D.	If you do not understand why you received a particular score on your assignment; you should ask your instructor.