Which of the following is an example of a condensation polymer?

The correct answer is option 3. Nylon-6,6.

An example of a condensation polymer among the options provided is Nylon-66.

Nylon-6,6 is a polyamide polymer formed through condensation polymerization of adipic acid and hexamethylenediamine. During the polymerization process, water is eliminated as a byproduct, and the monomers link together to form long chains of repeating units, resulting in the formation of Nylon-6,6.

Therefore, the correct option is Nylon-6,6.

In formation of nylon-6,6 loss of water molecule takes place so that it is condensation polymer.