When a hole of diameter ‘d’ is punched in a metal of thickness 't', then the force required to punch a hole is equal to (where $${\tau _{\text{u}}}$$ = Ultimate shear strength of the material of the plate)

A. $${\text{dt}}{\tau _{\text{u}}}$$

B. $$\pi {\text{dt}}{\tau _{\text{u}}}$$

C. $$\frac{\pi }{4} \times {{\text{d}}^2}{\tau _{\text{u}}}$$

D. $$\frac{\pi }{4} \times {{\text{d}}^2} \times {\text{t}}{\tau _{\text{u}}}$$

Answer: Option B