Hey there. cOvalent bonds consisting sharing of electrons, generally between non-metals, in order to gain 8 electrons, each atom. As for metals, their bond is metallic and more a non-metal+metal, it is ionic, as the metal loses and th non-metal gains electrons. Methane, made up of two non-metals, hydrogen and Carbon are a typical example of a covalent bond. As carbon adds his 4 electrons to the 4 of Hydrogen, by octet rule, it ends up with 8 electrons around it. Hence, the answer is B. Hope you understood it.
