Polyesters are formed from the reaction of
a.
a diamine and a dicarboxylic acid
b.
an alkene and a dicarboxylic acid
c.
a diol and a dicarboxylic acid
d.
a diol and an amino acid

The answer is C. a diol and a dicarboxylic acid

Explanation:

Because Esterification (formation of an ester) is a process that requires an alcohol to react with a carboxylic acid.

Polyester means many ester units.

one alcohol + one carboxylic acid make one ester

thus more than one of each functional groups will make more than on ester unit.

That is why diol (2OH functional groups) + dicarboxylic acid (2 Carboxyl groups) will make polyesters.

im not exactly sure but i think its b!