The element used for making solar cells is A. Magnesium B. Sodium C. Calcium D. Silicon

The correct answer is: D. Silicon

Silicon is the most common element in the Earth’s crust, and it is also the most common element used in solar cells. Solar cells are made of semiconductor materials, which are materials that can conduct electricity under certain conditions. Silicon is a semiconductor material, and it is able to convert sunlight into electricity.

Magnesium, sodium, and calcium are all elements that are also used in solar cells, but they are not as common as silicon. Magnesium is used in some types of solar cells, but it is not as efficient

Silicon is the best element for making solar cells because it is abundant, it is efficient, and it is relatively inexpensive.