What are the two key actions that all oil rings must perform?

The two key actions that all oil rings must perform are to distribute oil and control its amount on the cylinder wall. This function is crucial because oil is essential for lubricating the engine's moving parts, reducing friction, and preventing wear. By effectively distributing oil, the rings ensure that there is an adequate film of lubricant on the cylinder walls, which not only aids in smooth operation but also helps to manage temperatures and minimize the risk of engine damage due to heat or excessive friction. Controlling the amount of oil on the cylinder wall is equally important as too much oil can lead to unwanted oil consumption and fouling of spark plugs, while too little can lead to increased wear or even engine seizure.

The other options do touch on related themes in engine operation, but they do not capture the primary functions of the oil rings as precisely. For instance, while sealing the cylinder and enhancing durability are important for overall engine performance, they pertain more to the piston rings rather than the specific role of oil rings. Collecting excess fuel and diverting it does not relate to the primary function of oil rings, which is focused on oil distribution and management. Therefore, option B accurately highlights the essential responsibilities that oil rings fulfill in an engine's operation.