Which of the following statements is/are correct

(ABC) Due to their high bond dissociation energies, the M-M bonds in carbon and silicon (C - C bond Si - Si) are extremely stable. 
In carbon atom, the number of 4 valence electrons is equal to the valence orbitlas (one 2s + three 2p). Thus carbon is tetravalent state is fully saturated, because it has neither vacant orbital nor any lone pair of electrons on its atom due to which C- C bond is extremely stable.