There are two bags one of which contains 3 black and 4 white balls while, other contains 4 black and 3 white balls. A die is cast, if the face 1 or 3 turns up, a ball is taken from first bag and, if any other face turns up a ball is chosen from second bag. The probability of choosing black ball is
1
\(\frac{8}{22}\)
2
\(\frac{9}{22}\)
3
\(\frac{11}{21}\)
4
\(\frac{13}{21}\)