The correct option is D CH3−CH2−CH3
Catenation is the ability of the atoms of an element to combine among themselves and form long chains. Since carbon atom has a valency of 4, they can keep on forming long chains unlike oxygen or other elements. Depending on the number of double or triple bonds present in the long chain carbon compound, we can obtain wide varieties of compounds with vivid properties.
Here, propene (CH2=CH−CH3 ) and propane ( CH3−CH2−CH3 ) are two different carbon chains which have different types of bonds and uses catenation to form long chains.