Select the set in which the numbers are related in the same way as 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, 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.)
(30, 49, 19)
(37, 39, 2)

Given: (30, 49, 19); (37, 39, 2)

Logic: Add the first and the third number to get the second number.

Let's check each option:

First option: (7, 29, 22); 7 + 22 = 29

Second option: (37, 58, 18); 37 + 18 = 55 $$\neq$$​ 58

Third option: (17, 32, 12); 17 + 12 = 29 $$\neq$$​ 32

Fourth option: (18, 42, 21); 18 + 21 = 39 $$\neq$$​ 42

So, the correct answer is (a).