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 its constituent digits. E.g. 13 – Operations on 13 such as adding /deleting /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)
(21, 3 , 15)
(49, 7, 35)

(21, 3 , 15)

(49, 7, 35)

Logic: ​Third number = First number − (2 × Second number)

21 − (2 × 3) = 21 − 6 = 15

49 − (2 × 7) = 49 − 14 = 35

Now, check each option:

84 − (2 × 12) = 84 − 24 = 60 (Follow)

85 − (2 × 12) = 85 − 24 = 61 $$\not=$$​ 60

84 − (2 × 12) = 84 − 24 = 60 $$\not=$$ 62

85 − (2 × 13) = 85 − 26 = 59 $$\not=$$ 60

Thus, the correct option is: (b)