If y is the distance in the cross-stream direction from the centre line at a particular cross-section b Cross-stream half width. The mean velocity gradients and all the velocity fluctuations become zero when the value ( frac{y}{b} ) ___________

If y is the distance in the cross-stream direction from the centre lin

1.	If y is the distance in the cross-stream direction from the centre line at a particular cross-section b Cross-stream half width. The mean velocity gradients and all the velocity fluctuations become zero when the value ( frac{y}{b} ) ___________
A.	goes above unity
B.	goes below unity
C.	goes above zero
D.	goes below zero
Answer» B. goes below unity