500 ml of a hydrocarbon gas burnt in excess of oxygen yields 2500 ml of `CO_2` and 3 litres of water vapours. All volume being measured at the same temperature and pressure. The formula of the hydrocarbon is :
A. `C_5H_10`
B. `C_5H_12`
C. `C_4H_6`
D. `C_3H_6`