Question about Determine maximum shearing stress

The torques shown are exerted on pulleys A, B, and C. Knowing that both shafts are solid, determine the maximum shearing stress in (a) shaft AB, (b) shaft BC.

a) 97.21 MPa; 56.36 MPa

b) 94.38 MPa; 71.66 MPa

c) 85.14 MPa; 93.27 MPa

d) 78.32 MPa; 49.52 MPa