After interchanging + and -, 8 and 7, which one of the following becomes correct?
A. 8 - 7 + 3 x 5 = 35
B. 7 x 8 + 6 - 9 = 25
C. 13 + 8 x 3 - 7 = 0
D. 8 x 2 + 7 - 6 = 9​