The correct answer is B) check the overload relay for tripped condition, reset as necessary. The reasoning behind this is that if the motor will not start when the "off-run" switch is placed in the run position, the issue is likely related to the motor's overload protection circuit. The overload relay is designed to trip and interrupt the circuit if the motor draws excessive current, which could indicate an issue with the motor or the connected load. Checking the overload relay for a tripped condition and resetting it as necessary would be the logical first step to troubleshoot the problem. The other options are not as relevant in this scenario. Checking the overload relay heaters (A) or the main contactor coil (D) may be necessary if the overload relay is found to be faulty, but would not be the logical first step. Checking the disconnect switch (C) is not directly related to the issue of the motor not starting.