The correct answer is: A. battery.
A megger is a high-voltage insulation tester used to test the insulation resistance of electrical equipment. It consists of a high-voltage generator, a voltmeter, and an ammeter. The generator produces a high voltage, which is applied to the insulation under test. The voltmeter measures the voltage across the insulation, and the ammeter measures the current flowing through the insulation. The insulation resistance is calculated by dividing the voltage by the current.
The generator in a megger can be powered by a battery, a permanent magnet DC generator, or an AC generator. However, the most common type of generator used in meggars is a battery. This is because batteries are reliable and provide a constant voltage.
Permanent magnet DC generators are also reliable, but they can be more expensive than batteries. AC generators are less reliable than batteries or permanent magnet DC generators, and they can produce a variable voltage. This can make it difficult to get accurate readings when using an AC generator to power a megger.
Therefore, the correct answer to the question “The electrical power to a meggar is provided by” is A. battery.