What are the enthalpies of $\sigma$-bond and $\pi$-bonds in an alkene?

• A
  $397 \ kJ \ mol^{-1}$ and $284 \ kJ \ mol^{-1}$
• B
  $284 \ kJ \ mol^{-1}$ and $397 \ kJ \ mol^{-1}$
• C
  $450 \ kJ \ mol^{-1}$ and $300 \ kJ \ mol^{-1}$
• D
  $300 \ kJ \ mol^{-1}$ and $450 \ kJ \ mol^{-1}$