The relative molecular mass of a gas is 56 and its empirical formula is \({\text{C}}{{\text{H}}_{\text{2}}}\). What is the molecular formula of the gas?

A.     \({\text{C}}{{\text{H}}_{\text{2}}}\)

B.     \({{\text{C}}_{\text{2}}}{{\text{H}}_{\text{4}}}\)

C.     \({{\text{C}}_{\text{3}}}{{\text{H}}_{\text{6}}}\)

D.     \({{\text{C}}_{\text{4}}}{{\text{H}}_{\text{8}}}\)

D