The following type of bonding is strongly directional in solids.

ANS:D - Covalant

The type of bonding that is strongly directional in solids is covalent bonding. Covalent bonds are formed by the sharing of electrons between atoms, and the directionality arises from the specific orientation of the atomic orbitals involved in the bond formation. This directional bonding is particularly evident in covalent network solids like diamond or silicon, where atoms are bonded together in a specific arrangement with strong directional bonds.