Which type of lubrication method involves a part dipping into the lubricant?

The correct choice is splash lubrication. This method involves a rotating part that dips into a lubricant reservoir, allowing the lubricant to be splashed onto the surfaces that require lubrication. This technique is commonly used in applications such as engines and gearboxes, where parts are submerged or partially submerged in oil, and the movement of those parts generates splashes that distribute lubricating oil to areas needing protection and smooth operation.

In contrast, the other lubrication methods function differently: drip lubrication involves precise control of lubricant flow, often through a system that drips oil onto parts; manual lubrication typically requires an operator to apply the lubricant directly, often with a grease gun or oil can; and forced lubrication utilizes a pump to circulate the lubricant under pressure to various components, ensuring a consistent and rapid supply of oil, which is particularly critical in high-speed or high-load applications.