Answer
The correct option is (c) is sometimes ionic.
Work Step by Step
Carbon has four electrons in its valence and it needs four electrons to complete its octet. Carbon makes four covalent bonds by sharing four electrons in valence shell with other atoms. Carbon can form covalent bonds with other carbons by sharing electrons in the valence shell. Carbon atoms can make long chains for example hydrocarbons are the chains of carbon atoms in which carbon atoms are bonded to each other and hydrogen atoms. Carbon atoms can make double bonds with another atom by sharing two electrons in the valence shell-like C=O. Therefore, the options (a), (b), (d), and (e) are incorrect. Ionic bonds are formed by complete transfer of valence electron(s) between atoms. Carbon atom does not make ionic bonds because carbon has four electrons in its valence shell and for completing its octet by ionic bonding it has to either lose four electrons or gain four electron, which needs high energy, so is unfavorable. Hence, the correct option is (c) is sometimes ionic.
