Correct Answer - C
`DeltaH_("reaction")=sum{DeltaH_(f" "Fe(s))^(@)+DeltaH_(f" "CO" "(g))^(@)}-{DeltaH_(f" "FeO(s))^(@)+DeltaH_(f" "C("graphite"))^(@)}`
`=(0-110.5)-(-266.3+0)=155.8kJ" "mol^(-1)`
`DeltaS_("reaction")=sum[S_(Fe(s))^(@)+S_(Co(g))^(@)]-[S_(FeO(s))^(@)+S_(C("graphite"))^(@)]`
`=(27.28+197.6)-(57.49+5.74)`
`=161.65JK^(-1)" "mol^(-1)`
For spontaneous reaction, `T gt (DeltaH)/(DeltaS),T gt (155.8xx1000)/(161.65)`
`thereforeT gt 966K`