Probability of going left of peg = 1/2
probability of going right of peg = 1/2
After passing the first row, ball will hit a peg. so the probability of going left or right is 1/2.
Assume that ball goes to left:
Then the favorable outcome can be ball first going left then going right or ball first going right and then going left. Hence probability of ball hitting cell 2 after taking first left is = 1/2*1/2 = 1/4.
Now assume that ball goes to right:
The favorable outcome after taking right will be to take 2 left on next two pegs.
hence probability of hitting cell 2 after taking first right is 1/4 *1/2 =1/8
So the total probability = 1/8+1/4 =3/8
-------Analyze why option A in SC wrong-------