The correct option is A Water gas
The mixture of CO and H2 is called water gas. Hydrogen is made in large quantities in an inexpensive manner by passing steam over red-hot coke. This yields water gas, which is an important industrial fuel with a high calorific value. When it burns, it yields a lot of energy. C(s)+H2O(g)1250 K−−−−→CO(g)+H2(g)