A @ B means A is the sister of B;

A # B means A is the father of B;

A & B means B is the wife of A.

Based on the above information, find out which of the given statements can be the reason's behind the assertion made below if it is given that 'S @ M # T & U'

Assertion: S is the grand-daughter of Z?

Reason A: Z @ U

Reason B: Z @ M

​A @ B means A is the sister of B;

Expression: ​S @ M # T & U

From the given information Family tree will be: 

Assertion: S is the grand-daughter of Z?

Reason A: Z @ U

Hence, Reason A is NOT valid.​

Reason B: Z @ M

Thus, Reason B is also NOT valid.​

So, ​Neither A nor B is the reason behind the assertion.

Thus, the correct option is: (d)