Which statement concerning a lubricating oil's viscosity and bearing loading characteristics is true?

Correct Answer: Option B — Shaft bearings associated with relatively high torque loads and low rotational speeds require a lubricating oil with a relatively high viscosity.

High torque loads and low rotational speeds require a thicker, higher viscosity oil to maintain a robust lubricating film that resists being squeezed out of the bearing clearance. Conversely, high-speed, low-load applications require lower viscosity oils to reduce drag and prevent excessive heat buildup within the bearing assembly.