Statement (A) : $\sigma$  bond has independent existence.

Statement (B) : Free rotation of atoms is not possible around  $\pi$ - bond

 Statement (C) : $\pi$  - bond is more reactive than $\sigma$   bond.

The $\sigma$ bond may exist either alone or along with $\pi$ bonds.

 Free rotation is not possible around the $\pi$ bond.

$\pi$ bonds are more reactive because electron cloud is more exposed to attacking species.

All the three statements are correct.  Hence option A is correct answer.