Answer:
c. end-to-end overlap of two p orbitals
Step-by-step explanation:
A Pi bond is a covalent bond established by two atomic orbitals overlapping side-to-side. The combinations of these two atomic orbit may be px-px or py-py. A pi bond can be bonding or antibonding, identical to the sigma bonding.
hence the correct option for the question is c. end-to-end overlap of two p orbitals
