Final answer:
Both Technician A and Technician B could be right, as a blown bulb or a poor connection at the bulb socket could cause an inoperative rear stop light.
Step-by-step explanation:
Both Technician A and Technician B could be correct in diagnosing the cause of the inoperative rear stop light. A blown bulb could indeed cause the stop light to be inoperative, as the filament inside the bulb may have burned out. On the other hand, a poor connection at the bulb socket could also prevent the bulb from functioning properly, as it would interrupt the flow of electricity. Therefore, both Technician A and Technician B could be right.