All three of these names represent names of organic compounds, which are compounds that primarily have carbon and hydrogen as their principal atomic constituents. Carbon has the ability to form long chains of carbon atoms linked together, due to the fact it has four single electrons in its outer electron shell. An alkane would be where the carbon atoms are singly linked together, and the interior carbon atoms would have two hydrogen atoms to fill in the electrons for the other two electrons. Compound "A" would be the alkane, probably pentane, since there are 5 carbons present. An alkene has the presence of a double-bond, eliminating the need for two hydrogen atoms on the interior carbon atoms, so compound "B" would represent the alkene, probably 1,3-pentene to indicate where the double-bonds occur. An alkyne has a triple bond, taking two of the three hydrogen bond spaces out, so compound "C" would be the alkyne, ethyne because the triple bond occurs between the only two carbon atoms present.