Three of the following four are alike in a certain way and thus form a group. Which is the one that does NOT belong to that group?
(NOTE: Operations should be performed on the whole mumbers, without breaking down the numbers into its constituent digits. E.g., 13-Operations on 13 such as adding /subtracting/multiplying etc. to 13 can be performed. Breaking down 13 into 1 and 3 and then performing mathematical operations on 1 and 3 is not allowed)

Correct option is A

Logic: (I number – II number)×3
46 - 41 - 12 : (46 - 41) × 3 = 5 × 3 = 15 ≠ 12.
16 - 9 - 21 : (16 - 9) × 3= 7 × 3 = 21.
23 - 18 - 15 : (23 - 18) × 3 = 5 × 3 = 15.
34 - 28 - 18 : (34 - 28) × 3 = 6 × 3 = 18.