If ZERO is encoded as ADSN, then how do you encode STOP?
- (a) SPOT
- (b) TSPO ✓ UPSC's answer
- (c) TSOP
- (d) POST
Why the answer is (b)
• ZERO → ADSN: Z + 1 = A, E − 1 = D, R + 1 = S, O − 1 = N. The letters alternately move forward and back by one.
• STOP: S + 1 = T, T − 1 = S, O + 1 = P, P − 1 = O.
• So STOP is coded TSPO: (b).
Why the other options are wrong
- (a) SPOT
- SPOT does not follow the +1, −1 pattern.
- (c) TSOP
- TSOP shifts only the first two letters.
- (d) POST
- POST simply reverses the word.
Asked in the CSAT Paper II of the UPSC Civil Services Preliminary Examination 2026, held on 24 May 2026. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.