Three urns A, B and C contain 7 red, 5 black; 5 red, 7 black and 6 red, 6 black balls, respectively. One of the urn is selected at random and a ball is drawn from it. If the ball drawn is black, then the probability that it is drawn from urn A is :
1
\(\frac{4}{17}\)
2
\(\frac{5}{18}\)
3
\(\frac{7}{18}\)
4
\(\frac{5}{16}\)