In the following question, select the related letter pair from the given…

1. Identify the pattern in "PONL : PRST":
  - Reverse the word: PONL -> LNOP.
  - Apply a shift of +4 to each letter (L+4=P, N+4=R, O+4=S, P+4=T).
  - Result: PRST.
2. Apply the same pattern to "TONG":
  - Reverse the word: TONG -> GNOT.
  - Apply the shift of +4:
    - G (7) + 4 = 11 (K)
    - N (14) + 4 = 18 (R)
    - O (15) + 4 = 19 (S)
    - T (20) + 4 = 24 (X)
3. Result: KRSX.
Final Answer: Option C