Why does carbon form such a large number of compounds?

Knowing that carbon is a non-metal element in the periodic table and that non-metals are electronegative and form bonds by sharing electrons can help us answer this issue. Self-linking between an element's atoms results in the formation of many compounds.

Carbon is a group14 element with a valency of four. It can bond with four different atoms. Thus, it has tetravalency that contributes to its number of compounds.

Catenation is the property of bonding with atoms of the same element. The catenation property also causes a large number of carbon compounds. Due to this property carbon forms double and triple bonds with other carbon atoms.

Hence, the correct option is (D).