Which one is stronger,$\sigma$ bond or $\pi$ bond? Why?

(A) The $\sigma$ bond is stronger than the $\pi$ bond.
The strength of a covalent bond depends on the extent of overlapping of atomic orbitals.
In the formation of a $\sigma$ bond,the atomic orbitals overlap along the internuclear axis (head-on overlap),which results in a greater extent of overlapping.
In the formation of a $\pi$ bond,the atomic orbitals overlap sideways (lateral overlap),which results in a smaller extent of overlapping.
Since the strength of a bond is directly proportional to the magnitude of overlapping,the $\sigma$ bond is stronger than the $\pi$ bond.