A capacity rating expressed in ampere hours is commonly associated with what type of device?

A capacity rating expressed in ampere hours is a standard measure used to describe the energy storage capability of storage batteries. This measurement indicates how much current a battery can deliver over a specified period, which is crucial for understanding how long a battery can power a device before needing to be recharged.

In contrast, light bulbs are typically rated in watts, which measure the power consumption rather than energy storage. Electric motors are rated by their horsepower or watts and focus on output capacity for mechanical work. Generators have ratings based on their power output, usually indicated in kilowatts or megawatts, which reflects their capacity to generate electrical energy. Thus, the association of ampere hours directly correlates to the function and application of storage batteries, confirming that option B is the appropriate choice.