Answer :
When replacing a tapered roller bearing, its race must be replaced too, as it is crucial for proper bearing function and to prevent premature failure. Thus option (D) Race. is the correct option.
Whenever a tapered roller bearing is replaced, its race must be replaced with it. The race, also known as the bearing race, is a hardened surface against which the bearings roll. It is essential for the correct functioning of the bearing assembly and is specifically tailored to the geometry of the bearings. If the race is not replaced along with the bearings, premature bearing failure can occur due to imperfect mating surfaces, which can lead to uneven wear and tear. This is why when replacing a tapered roller bearing, it is crucial to also replace its race to ensure proper fit and function.