Which among the following compounds has a double bond?

Ethane (C2H6) molecule has single bonds between each carbon atom and its three hydrogen atoms. Methane has a single carbon atom bonded to four hydrogen atoms through four single covalent bonds. Acetylene (C2H2) molecule has a triple bond between the two carbon atoms and a single bond between each carbon and a hydrogen atom. Ethylene has a double bond between the two carbon atoms and two single bonds between each carbon and a hydrogen atom.