$C=A\ast B$
$\implies C=\overline{A}\;\;\overline{B}+AB$
$\implies C = \overline{A\text{ XOR }B}$
$\implies C = A\text{ XNOR }B$
Truth table is: $${\begin{array}{ccc}\hline
\textbf{A}& \textbf{B}& \textbf{C} \\\hline
0& 0 & 1 \\
0& 1& 0\\
1& 0& 0 \\
1&1&1
\end{array}}$$ When $C = 1 $, observing the truth table we can say $ A=B.$