Statement (A) : Hybrid orbitals always form only $\mathrm{\sigma }$ bonds. 

Statement (B) : Only orbitals undergo hybridization but not electrons 

Statement (C) : Hybrid orbitals form $\mathrm{\sigma }$ and $\mathrm{\pi }$ bonds

$\mathrm{\sigma }$ bonds are more stable then $\mathrm{\pi }$ bonds. The hybrid orbitals always form stable bonds $\left(\mathrm{\sigma }\right)$The meaning of orbital is the probability for finding an electron is maximum around the nucleus. So the orbitals undergo hybridization.

Hybrid orbitals form $\mathrm{\sigma }$ bonds only, but not $\mathrm{\pi }$bonds. Because $\mathrm{\sigma }$  bonds are stable bonds.