When traction is poor (wet/icy roads), the retarder (engine brake) can cause:

The drive wheels to skid.. Section 2.13: Retarders can cause the drive wheels to skid when traction is poor. Turn them off.

When traction is poor (wet/icy roads), the retarder (engine brake) can cause:

ANSWER BREAKDOWN
  • A. Incorrect. "Better control." is not correct. Retarders can cause the drive wheels to skid when traction is poor. Turn them off.
  • B. Correct. Retarders can cause the drive wheels to skid when traction is poor. Turn them off.
  • C. Incorrect. "The engine to stall." is not correct. Retarders can cause the drive wheels to skid when traction is poor. Turn them off.
  • D. Incorrect. "Better braking." is not correct. Retarders can cause the drive wheels to skid when traction is poor. Turn them off.