What is the physical relationship between engine Torque ($M$, in Nm), engine Power ($P$, in kW), and engine Rotational Speed ($n$, in RPM) in a heavy commercial vehicle diesel engine?

1. $$P = (M · 2π · n)/(60,000)$ (Power is proportional to the product of Torque and Rotational Speed)
2. $$P = M + n$ (Power is the sum of torque and RPM)
3. $$M = P · n$ (Torque is power multiplied by RPM)
4. Torque and Power are identical physical quantities expressed in different units