A good lubricant should be highly
A: Viscous and velocity
B: Non viscous volatile
C: Viscous and non-volatile
D: Transparent

Hint: A lubricant or a lube is a substance that helps to reduce the friction between two bodies in contact. It usually exists in a liquid form and it is applied between the two surfaces where friction occurs. This causes the system to produce less heat energy and also it enhances the efficiency of the working of this system. This is the key principle behind lubricants and we can approach this question by keeping these points in our mind.

Complete step by step answer:
A lubricant must possess certain properties that makes them available for use in all the conditions, irrespective of the natural conditions around the system. It should be capable of reducing the friction between two bodies every time. A good lubricant must be stable thermally as well as hydraulically. It should prevent itself from oxidation and should avoid possibilities of corrosion. It is available as a liquid all the time. Hence to maintain its liquidity, it should have a high boiling point and a low freezing point.
Let us consider viscosity as we are dealing with that topic here. A good lubricant must possess a very high value of viscosity because only when there is a frictional force acting between the layers of the liquid, it can easily regulate the friction of other bodies.

So, the correct answer is “Option A”.

Note:
Esters, wax and fatty acids are some very commonly used lubricants for various applications. Motor oils used in various vehicles is a classic example of a lubricant. All these lubricants follow the above mentioned properties. Thus they are reliable.
A good lubricant must be stable thermally as well as hydraulically. It should prevent itself from oxidation and should avoid possibilities of corrosion.