Which of the following conditions is most likely to occur if the electric starter motor pinion gear fails to disengage from the flywheel of a diesel engine after the engine has started?

Correct Answer: Option B — Starting motor will dangerously overspeed

If the starter pinion fails to disengage, the rapidly accelerating diesel engine drives the starter armature far beyond its design RPM, causing catastrophic centrifugal failure and dangerous overspeeding.