Answer:
b. Technician B only
Explanation:
"Draining and refilling the gearbox: It is best to drain the oil just after a run, when it is warm and flows out quickly. Put the car on level ground, and make sure that you have enough new oil of the correct type for refilling."
Reference: Muir, Alex. “Checking the Gearbox Oil Level, Draining and Refilling.” How a Car Works, How a Car Works, 2019