From his experiments, $S.L.$ Miller produced amino acids by mixing the following in a closed flask

• A

  $CH _{3}, H _{2}, NH _{3}$ and water vapor at $600^{\circ} C$

• B

  $CH _{4}, H _{2}, NH _{3}$ and water vapor at $800^{\circ} C$

• C

  $CH _{3}, H _{2}, NH _{4}$ and water vapor at $800^{\circ} C$

• D

  $CH _{4}, H _{2}, NH _{3}$ and water vapor at $600^{\circ} C$