Explanation:

Alright, let’s break this down:

- The given pair is RS : IH. Let’s figure out the pattern.

- Count the alphabetical positions: R(18), S(19). I(9), H(8).

- Notice this: R?I (18?9) and S?H (19?8). Each letter is mapped to its reverse position in the alphabet: 27 - 18 = 9, 27 - 19 = 8! So, the pair is linked by reversing the position in the alphabet.

Let’s apply that to each option (“first letter” and “second letter” of each option):

1. TM : GN

- T(20) ? G(7); 27 - 20 = 7

- M(13) ? N(14); 27 - 13 = 14

2. BX : CY

- B(2) ? C(3); 27 - 2 = 25, not 3 ??

- X(24) ? Y(25); 27 - 24 = 3, not 25 ??

3. RS : IT

- R(18) ? I(9); 27 - 18 = 9

- S(19) ? T(20); 27 - 19 = 8 (not 20) ??

4. AJ : ZK

- A(1) ? Z(26); 27 - 1 = 26

- J(10) ? K(11); 27 - 10 = 17 (not 11) ??

Here’s the thing: only option 1 (TM : GN) perfectly follows the same rule as RS : IH for both letters.

The correct answer is Option 1: TM : GN.