Which statement about capacitors is true?

Capacitors are components that can indeed block DC current while allowing AC current to pass through, making the statement that they can block DC current accurate. This behavior is due to the way capacitors charge and discharge. When a DC voltage is applied, the capacitor will charge up to that voltage and then effectively become an open circuit, preventing further DC current from flowing.

In AC circuits, capacitors allow current to pass as they continuously charge and discharge in response to the changing voltage, which is why they are often used in filter and timing applications. They are also widely used in smoothing out fluctuations in power supplies.

The other options do not hold true: capacitors work in both AC and DC environments (not limited to AC), they do indeed store energy in the form of an electric field, and they do not inherently increase power consumption; rather, they influence reactive power and can contribute to more efficient power usage in some circuit designs.