কোন কয়েন টসে হেড আসার ঘটনা A={H} হলে   $A^{c}$ কি হবে?

A man has $3$ coins $A, B$ & $C$. $A$ is fair coin. $B$ is biased such that the probability of occurring head on it is $2/3$. $C$ is also biased with the probability of occurring head as $1/3$. If one coin is selected and tossed three times, giving two heads and one tail, find the probability that the chosen coin was $A$