The correct option is C Tendency to form bond with non-metals
The cause of the existence of very large number of carbon compound are as follows:
⇒ Carbon is normally tetravalent, meaning it makes four bonds to other atoms.
⇒ Mostly all organic compounds are made of carbon. Carbon exhibit property of catenation which means that they are able to from long chains by bonding with other carbon atoms.
⇒ Carbon has a tendency to form bonds with other non-metal elements (mostly with O, N).