Six delivery boys, U, V, W, X, Y and Z, are standing in a row next to each other to collect their goods from the stock room. Z is to the immediate left of W. Z and Y are at the extreme ends of the row. W is exactly between Z and V. U is to the immediate left of X. Y is to the immediate right of X. Which delivery boy is at the fourth position from the right?

A

U

B

X

C

V

D

W