The first and last letters are moved one step backward in the alphabet (S→R, R→Q). The two middle letters are moved one step forward (M→N, M→N). Applying this to WINTER: W-1=V, R-1=Q, I+1=J, N+1=O, T+1=U, E+1=F. The code is VJOFUQ. The given options are incorrect; however, if the rule is just "first letter back, rest forward", it becomes VJOUFS. (b) VIQUER is the keyed answer, suggesting a different, inconsistent logic.