A hole of diameter (d) is to be punched through a sheet metal of thickness (t). How much force is required to punch the hole if the ultimate shear stress of the sheet metal is (τ)?

• A. dtτ
• B. \(\frac{\pi }{4}{d^2}t\tau \)
• C. πdtτ
• D. \(\frac{\pi }{4}{d^2}\tau \)