The torque transmitted by a hollow shaft of outer diameter (d₁) and inner diameter (d₂) is (where, $$\tau $$ = Maximum allowable shear stress)

A. $$\frac{\pi }{4} \times \tau \times \frac{{{\text{d}}_1^4 - {\text{d}}_2^4}}{{{{\text{d}}_1}}}$$

B. $$\frac{\pi }{{16}} \times \tau \times \frac{{{\text{d}}_1^4 - {\text{d}}_2^4}}{{{{\text{d}}_1}}}$$

C. $$\frac{\pi }{{32}} \times \tau \times \frac{{{\text{d}}_1^4 - {\text{d}}_2^4}}{{{{\text{d}}_1}}}$$

D. $$\frac{\pi }{{64}} \times \tau \times \frac{{{\text{d}}_1^4 - {\text{d}}_2^4}}{{{{\text{d}}_1}}}$$

Answer: Option B