Final answer:
The speed rate on a power pipe cutter is primarily controlled by manual adjustment, allowing for customization based on pipe size and cut precision.
Step-by-step explanation:
The speed rate on a power pipe cutter is controlled by various factors, but in the context of the options provided, the correct answer is: A. Manual adjustment. Power pipe cutters typically feature adjustments that allow the user to control the speed at which the cutting blade or wheel interacts with the pipe.
This manual control ensures the tool can be adapted to different situations such as the size of the pipe or precision of the cut required. Factors like material type and the power source may indirectly affect the optimal speed rate, but the direct control is typically manual.