Assertion (A) : If the whole apparatus of YDSE is immersed in a liquid, then the fringe width will decrease
Reason (R ) : The wavelength of light in water is more than that of air.
A. A is true and R is true and R is the correct explanation of A.
B. A and R are true but R is not correct explanation of A
C. A is true, R is false
D. A is false, R is true.