Alkanes, alkenes, and alkynes are all hydrocarbons. What is one difference between alkanes and alkenes?A) Alkenes form a branched chain; alkanes form only straight chains.B) Alkenes are saturated hydrocarbons; alkanes are unsaturated hydrocarbons.C The characteristic functional group of an alkene is the carbon-carbon double bond.D) The characteristic functional group of an alkene is the carbon-carbon triple bond.