The correct answer is: D. Electrolytic
Explanation:
Capacitors are devices that store electrical energy in an electric field. They are made up of two conductive plates separated by an insulating material. The capacitance of a capacitor is measured in farads (F).
Air capacitors are the simplest type of capacitor. They are made up of two conductive plates separated by a layer of air. Air capacitors have a low capacitance and are not very efficient.
Paper capacitors are made up of two conductive plates separated by a layer of paper. Paper capacitors have a higher capacitance than air capacitors and are more efficient.
Mica capacitors are made up of two conductive plates separated by a layer of mica. Mica capacitors have a higher capacitance than paper capacitors and are more efficient.
Electrolytic capacitors are made up of two conductive plates separated by an insulating layer of aluminum oxide. Electrolytic capacitors have a very high capacitance and are very efficient. However, they are polarized and can only be used with DC voltage.
In conclusion, electrolytic capacitors are the only type of capacitor that can be used only for DC.