By interchanging the given two signs which of the following equation will be not correct?

+ and -

I. $$4 \times 6 + 7 - 3 \div 1 = 21$$
II. $$6 \times 9 + 7 - 8 \div 2 = 51$$

A

Only I

B

Both I and II

C

Neither I nor II

D

Only II