Answer: (b) neon
In its innermost shell, the carbon atom has two electrons and four valence electrons. When it forms covalent bonds with four univalent atoms, it gains an extra four electrons by sharing them. In its outermost shell, there are now 8 electrons. This is similar to neon’s electronic configuration, which is electronic configuration 2, 8.
The electron configuration of neon is
Ne(Z = 10) = 1s2 2s2 2p6