Verified Answer :

First you add 3+6, then take 9 and multiply by 2 which is 18, the do 26-18 which is 8×3=24.
12×3=36-12=24.
So 24=24
Your answer is A.

A=

left side    3 12 - 12 = 24     

right side    3
(26 - 2 * (3 + 6)) = 24