Which of the following is characteristic of an electrolytic capacitor?

Electrolytic capacitors use a very thin oxide layer as a dielectric, which allows them to pack a massive amount of capacitance into a small physical package. This makes them ideal for power supply filtering and low-frequency audio coupling where high capacitance values are necessary. They are not known for precision; they typically have very loose tolerances and higher leakage currents than ceramic or film types. Because their internal rolled construction often results in high equivalent series inductance, they are also a poor choice for RF applications, making the other options clearly incorrect.