Polymers are human made. synthetic subunit natural maromolecule

Synthetic

Explanation:

Synthetic polymers can be define as the human composed polymers. They can be classified into four main types: thermoplastics, elastomers, synthetic fibers, and thermosets.  

The thermoplastics are the polymers which can be molded, it get solidify on cooling.  

The thermostats are the polymers which resist any change in their shape, they are hard. They are often used in adhesives.

The elastomers are the polymers which can be characterized as a flexible polymers.  

Synthetic fibers polymers can be synthesized by improving the quality of natural plant and animal fibers.

i think the answer is a, hope this : )