A) $CH_3$, $H_2$, $NH_4$ and water vapor at 800°C
B) $CH_4$, $H_2$, $NH_3$ and water vapor at 600°C
C) $CH_3$, $H_2$, $NH_3$ and water vapor at 600°C
D) $CH_4$, $H_2$, $NH_3$ and water vapor at 800°C
Explanation
[Solution] Miller used $CH_4$, $H_2$, $NH_3$ and water vapour at 800°C with electric discharge. Answer (4).