15) Which of the these is a balanced chemical equation?
A) CO(g) + O2(g) → CO2(g)
B) CO(g) + 2O2(g) → 2CO2(g)
C) 2CO(g) + O2(g) → 2CO2(g)
D) 2CO(g) + 2O2(g) → 2CO2(g)