The correct answer is A. alkene.
Alkenes are unsaturated hydrocarbons that contain one or more double bonds between carbon atoms. They are named by adding the suffix -ene to the name of the corresponding alkane. For example, the alkene with two carbon atoms is called ethene, and the alkene with three carbon atoms is called propene.
Alkenes are important in organic chemistry because they are the building blocks of many other organic compounds. They are also used in a variety of industrial applications, such as the production of plastics and synthetic rubber.
Alkynes are unsaturated hydrocarbons that contain one or more triple bonds between carbon atoms. They are named by adding the suffix -yne to the name of the corresponding alkane. For example, the alkyne with two carbon atoms is called ethyne, and the alkyne with three carbon atoms is called propyne.
Alkynes are less common than alkenes, but they are still important in organic chemistry. They are used in a variety of industrial applications, such as the production of pharmaceuticals and pesticides.
Alkalis are a group of elements that are highly reactive with water. They are also known as bases. Alkalis have a pH of greater than 7.
Alkynes are not alkalis.