In the group $\left(G \otimes_{15}\right)$, where $G=\{3,6,9,12\}$, $\otimes_{15}$ is multiplication modulo 15 , the identity element is

The composition table is \begin{array}{lllll} \hline 15 & 3 & 6 & 9 & 12 \\ \hline 3 & 9 & 3 & 12 & 6 \\ \hline 6 & 3 & 6 & 9 & 12 \\ \hline 9 & 12 & 9 & 6 & 3 \\ \hline 12 & 6 & 12 & 3 & 9 \\ \hline \end{array} From the table 6 is the identity element.