Ray’s Radios believed the synergies between radio production and battery production could be realized if he expanded. However, due to overseeing the battery expansion Ray devoted less time to the radio business leading to the radio unit costs increasing. At this point, Ray’s Radios should

C. Shut down the production of the batteries

Explanation:

Since in the question it is mentioned that The Ray trust that the synergies between the radio production and the battery production is realized when it is expanded but by due to overseeing it ray spend less time to the radio business.

As from the above information provided first of all its trust is not be pratical. nor he search for an expansion he should more concentrate on the radio production as it is the main product