Which of the following light bulb types requires no ballast?

The correct answer identifies that both incandescent and LED light bulbs require no ballast. Incandescent bulbs operate by passing electricity through a filament, which heats up and produces light. This simple electrical mechanism does not need a ballast, which is a component typically required for controlling current in certain other types of lighting.

LED (Light Emitting Diode) bulbs also do not require a ballast. Instead, they rely on a driver that regulates the power supplied to the LED chips, ensuring they operate safely and efficiently. This driver is built into the LED bulb itself or can be part of the fixture.

In contrast, fluorescent bulbs do require a ballast to start and regulate the electrical current flowing through the gas in the tube. Halogen bulbs, which are a type of incandescent light and contain halogen gas to improve efficiency, also do not need a ballast but utilize different operational technology. By focusing on incandescent and LED bulbs as the correct answer, it highlights their straightforward functionality without the need for external components to regulate their operation.