Answer:
The correct answer would be A) CUA.
It can be explained with the help of base-pair complementarity rule. It states that adenine always base-pairs with thymine and guanine always base-pairs with cytosine.
In addition, in RNA, thymine is replaced with uracil and thus adenine base-pairs with uracil.
Anti-codon site of tRNA and codon site of mRNA are also complementary in nature.
Thus, in codon GAU, G would base-pair with C, A would base-pair with U, and U would base pair with A.
Hence, the correct anti-codon would be CUA.