Clearly, each letter of the word ALTERED is replaced by the letter which occupies the same position from the other end of the English alphabet, to obtain code.
Thus, A, the first letter of the alphabet, is replaced by Z, the last letter.
L, the 12th letter from the end.
T, the 7th letter form the end of the alphabet is replaced by G, the 7th letter from the beginning of the alphabet, and so on.
Similarly, in the word RELATED, R will be coded as I, (E as V), (L as O), (A as Z), (T as G) and (D as W).
Thus, the code becomes IVOZGVW.
Hence, the answer is (a).