Select the set in which the numbers are related in the same way as are the numbers of the following sets.
(NOTE: Operations should be performed on the whole numbers, without breaking down the numbers into their constituent digits. E.g. 13 – Operations on 13 such as adding/subtracting/multiplying to 13 can be performed. Breaking down 13 into 1 and 3 and then performing mathematical operations on 1 and 3 is not allowed.)
(14, 66, 19)
(43, 134, 24)​

logic: (1st + 3rd) × 2 = 2nd
Check the original sets:
(14, 66, 19) → (14 + 19) × 2 = 33 × 2 = 66 
(43, 134, 24) → (43 + 24) × 2 = 67 × 2 = 134 
Now test the options:
A. (10, 35, 8) → (10 + 8) × 2 = 18 × 2 = 36 ≠ 35 
B. (45, 97, 4) → (45 + 4) × 2 = 49 × 2 = 98 ≠ 97 
C. (6, 42, 15) → (6 + 15) × 2 = 21 × 2 = 42 = 42
D. (37, 81, 4) → (37 + 4) × 2 = 41 × 2 = 82 ≠ 81 
Correct Answer is (C) (6, 42, 15)​​