When a machine member is subjected to torsion, the torsional shear stress set up in the member is
A. Zero at both the centroidal axis and outer surface of the member
B. Maximum at both the centroidal axis and outer surface of the member
C. Zero at the centroidal axis and maximum at the outer surface of the member
D. Maximum at the centroidal axis and zero at the outer surface of the member
Answer: Option C

In question askes machine member, not a shaft.
So, answer B is right
The answer should be B
Option C is right answer
C is right answer