The first member of the alkyne series is
Step 1:
The compounds containing Carbon atoms have multiple bonds between two Carbon-Carbon atoms are called unsaturated hydrocarbons.
The multiple bonds are either double or triple bonds.
Step 2:
The explanation for the correct option:
Alkenes and alkynes contain double and triple bonds between Carbon-Carbon atoms respectively. So these are known as unsaturated hydrocarbons.
The general formula of alkynes is .
The first member of the alkyne series is Ethyne .
The explanation for the incorrect option:
Methane is a saturated hydrocarbon because it contains only a single bond between Carbon and Hydrogen atoms.
Ethene is an unsaturated hydrocarbon because it contains double bonds between two Carbon-Carbon atoms.
Propene is an unsaturated hydrocarbon because it contains double bonds between two Carbon-Carbon atoms.
Final answer:
Hence, option (C) is the correct option.