The torque required to overcome viscous resistance of a footstep bearing is (where μ = Viscosity of the oil, N = Speed of the shaft, R = Radius of the shaft, and t = Thickness of the oil film)

A. μπ²NR/60t

B. μπ²NR²/60t

C. μπ²NR³/60t

D. μπ²NR⁴/60t

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