Answer: Option (d) is the correct answer.
Explanation:
A covalent bond is defined as the bond formed by sharing of electrons between the two chemically combining atoms.
For example, atomic number of chlorine is 17 and it has 7 valence electrons.
To attain stability it need to gain one more electron.
So, when one chlorine atom chemically combines with another chlorine atom then there occurs sharing of electrons between the two. As a result, there will be sharing of electrons.
A molecule is defined as the specie that contains same type of atoms which are chemically combined together in a fixed ratio by mass.
