Q.

Assertion (A):

both compounds will have zero dipole moment.

Reason (R): –CN group is linear but –SH group is non linear with benzene ring.

1 Assertion (A) is True, Reason (R) is True; Reason (R) is a Correct explanation for Assertion (A)  
2 Assertion (A) is True, Reason (R) is True; Reason (R) is NOT a Correct explanation for Assertion (A)  
3 Assertion (A) is True, Reason (R) is False  
4 Assertion (A) is False, Reason (R) is True  

Ans.

(4)