Mike used the computation StartFraction 7 Over (6 + 8 + 7) almost-equals 0.33 = 33 percent to find the percentage of eighth-grade band members who can play more than one instrument. What error did Mike make?
A. Mike included 7 when finding a sum to use as the denominator of his fraction.
B. Mike used the total of the column containing 7 as his denominator instead of the total of the row containing 7.
C. Mike should have used the sum of all the cell values as his denominator.
D. Mike should have used the number of eighth-grade students who can only play one instrument as the denominator of his fraction.