Latex of some plants containing long chain hydrocarbons is considered to be a good substitute for liquid fuels or petroleum. Such plants having large amount of latex with long chain hydrocarbon are called petroplants. Cultivation of petroleum is also a part of energy cropping . cultivation of these petrocrop was first of all done by Italians in Ethiopia about fifty year back. Although actual credit for identifying the petrocrop crops goes to Dr. Calvin. The most common petroplants belongs to family
Euphorbiaceae, Asclepiadaceae, Apocynaceae, Compositae, Labiatae, Sapotaceae, urticaceae etc. which have property of converting large amount of their photosynthesis into latex with hydrocarbons.
So, the correct option is 'All of the above'.