If 9 # 3 @ 4 = 31 and 8 # 7 @ 2 = 58, then what will be 5 # 6 @ 7?

Correct option is C

Let # → × and @ → +
9 # 3 @ 4 = 31
9 × 3 + 4 = 31
27 + 4 = 31
31 = 31
And
8 # 7 @ 2 = 58
8 × 7 + 2 = 58
56 + 2 = 58
58 = 58
Similarly,
5 # 6 @ 7
5 × 6 + 7
= 30 + 7
=37