The transfer RNA anticodon for the messenger RNA codon G - C - A &...

The transfer $RNA$ anticodon for messanger $RNA$ codon $G - C - A$ is

$C - G - U$, because in anticodon of $RNA$,

$G$ replaced by $C$
$C$ replaced by $G$
$A$ replaced by $U$

Here, C(cytosine) forms triple bond with G (guanine) and A (adenine) forms double bond with U (uracil).