Table 1 is a part of MS Excel worksheet which shows the mark obtained by some students in an examination. Use the table to answer questions 20 and 21.

S/N	A	B	C	D	E	F
1	NAME OF STUDENT	ENGLISH LANGUAGE	MATHEMATICS	DATA PROCESSING	COMPUTER STUDIES	CIVIC EDUCATION
2	ANENE LORRETA	65	90	70	85	65
3	BAKARE IMAN	60	65	75	80	75
4	ENEH GRACE	75	65	65	75	60
5	MOHEMMED DEJI	65	60	65	60	60
6	ONYEBUEKE DEBORAH	89	65	60	60	65

Which of the following formulas would calculate the average score of the students in Mathematics?