What can't be measured with a multimeter?

A multimeter is a versatile tool that can measure various electrical parameters, including voltage (both AC and DC), resistance, and current (again, both AC and DC). The correct answer highlights that a certain type of current measurement can present challenges.

In this case, while a multimeter is capable of measuring AC current, it often requires specific settings and probe configurations to do so effectively. In some scenarios, measuring AC current may be less straightforward than measuring other parameters due to the need for additional accessories, such as clamp attachments, or the limitations of the multimeter’s range. However, when properly configured, a multimeter can indeed measure AC current.

The understanding of what cannot be measured by standard multimeters hinges on the context of the question. While AC current is challenging, it is still possible; therefore, the answer indicates a misunderstanding of the capabilities of a multimeter rather than a lack of ability in measuring AC current altogether. It’s important to recognize the tool's versatility and the right conditions for effective measurements.