If PERFECT is coded as RGUIHFW, then BROWN in that code is written as

CSQYP
DSRZQ
CTRYQ
DTRZQ

The correct answer is (c).

In the given code, each letter is shifted 3 places forward in the alphabet. So, P becomes R, E becomes G, R becomes U, and so on.

Following this rule, B becomes C, R becomes T, O becomes S, W becomes Q, and N becomes Y. Therefore, BROWN in that code is written as CTRYQ.

(a) is incorrect because CSQYP is not the code for BROWN in the given code.
(b) is incorrect because DSRZQ is not the code for BROWN in the given code.
(d) is incorrect because DTRZQ is not the code for BROWN in the given code.