JEE Math Practice Question

There are three bags $$X, Y$$ and $$Z$$. Bag $$X$$ contains 5 one-rupee coins and 4 five-rupee coins; Bag $$Y$$ contains 4 one-rupee coins and 5 five-rupee coins and Bag $$Z$$ contains 3 one-rupee coins and 6 five-rupee coins. A bag is selected at random and a coin drawn from it at random is found to be a one-rupee coin. Then the probability, that it came from bag $$\mathrm{Y}$$, is :

1. A.$$\frac{1}{2}$$
2. B.$$\frac{1}{3}$$
3. C.$$\frac{5}{12}$$
4. D.$$\frac{1}{4}$$