Let C1 be a fair coin that has H on one side and T on the ot

Let C1 be a fair coin that has H on one side and T on the other side. Let C2 be a coin that has H on both sides. We choose one of C1 and C2 uniformly at random and flip it. Define the events
A = “we choose C2”,
B = “the flip resulted in H”.
What is the conditional probability Pr(A | B)?
(a) 1/3
(b) 1/2
(c) 2/3
(d) none of the above

Please explain briefly?

Solution

c) 2/3 becuse head can be obtained on both the coins. hence using baye\'s theorem P(A?B) = 2/3