What is true of a covalent bond?
a. it is the electrostatic attraction between oppositely charged particles..
b. it is the sharing of electrons by overlapping orbitals.
c. it involves the exchange of electrons from one atom to another.
d. it involves the sharing of neutrons between two nuclei.

The covalent bond is the sharing of electrons by overlapping orbitals.

B

Explanation

Covalent bond is defined as the bonding formed by mutual sharing of two or more valence electrons between the elements.

It obeys valence bond theory. The mutual sharing of valence electrons occurs by overlapping of the valence orbitals as stated by valence bond theory.

The mutual sharing of valence electrons lead of stabilize both the elements.

The electrons are not transferred completely to another element for stabilizing purpose.

The valence electrons will remain in their parent element shell only, but they will be shared with another element valence shell electrons by overlapping.

So the option (b) is true for covalent bond, the remaining options (A) and (C) are true for ionic bond.