The right answer is b. Covalent
The covalent bond represents a particular type of chemical bond. It corresponds to the bond between two atoms, generally non-metallic, resulting from the pooling of electrons coming separately from each of them. Thus, each atom gains in electrons.
The electrons involved in a covalent bond form pairs, or doublets, of binding electrons. When the atoms share two doublets, we speak of double bond; when they share three doublets, we speak of triple bond.
