Final answer:
The correct answer is non-fibrous lubricant because it has a smooth consistency that does not form strings when stretched between the fingers.
Step-by-step explanation:
The lubricant that will most likely leave no strings of grease when you put a small amount between two fingers and then spread them apart is non-fibrous. Grease tends to be thick and can form strings or threads when stretched between fingers due to its viscous nature. On the other hand, non-fibrous lubricants are designed to have a smooth consistency and do not contain fibers or particulates that would contribute to string formation. Therefore, option A, non-fibrous, is the correct answer as it is most likely to separate cleanly without leaving strings between the fingers.