A hydrocarbon 'X' with the formula C₆H₈ uses two moles of H₂ on catalytic hydrogenation of its one mole. On ozonolysis, 'X' yields two moles of methane dicarbaldehyde. The hydrocarbon 'X' is:
(a) Propene
(b) Butene
(c) Pentene
(d) Hexene