21.) The technician finds that one of the rocker arms is badly worn in the area of the pushrod contact. Technician A says that a clogged oil passage in the pushrod could be the cause. Technician B says that a cracked valve seat could be the cause. Who is right? OA. A only B. B only OC. Both A and B OD. Neither A nor B

## Step 1<br />This problem is related to the field of automotive engineering, specifically focusing on the potential causes of wear in a rocker arm. The rocker arm is a crucial component in an internal combustion engine, responsible for opening and closing the valves. The wear in the rocker arm can be caused by several factors, including a clogged oil passage in the pushrod or a cracked valve seat.<br /><br />## Step 2<br />Technician A suggests that a clogged oil passage in the pushrod could be the cause of the wear in the rocker arm. This is a plausible explanation because the pushrod is responsible for transmitting oil pressure to the rocker arm. If the oil passage is clogged, it could lead to inadequate lubrication, which in turn could cause wear in the rocker arm.<br /><br />## Step 3<br />Technician B, on the other hand, proposes that a cracked valve seat could be the cause of the wear in the rocker arm. This is also a plausible explanation because the valve seat is where the valve meets the cylinder head. If the valve seat is cracked, it could cause the valve to open and close unevenly, leading to wear in the rocker arm.<br /><br />## Step 4<br />Given that both Technician A and Technician B provide plausible explanations for the wear in the rocker arm, it can be concluded that both are correct.