A plant with purple flowers is allowed to self-pollinate. Generation after generation, it produces purple flowers. This is an example of a. hybridization. b. incomplete dominance. c. true-breeding. d. the law of segregation. e. polygenetics.

Explanation:

A true breeding: it  is a kind of breeding in which the parents would produce offspring that all the offspring  would contain the same phenotype.

This means that the parents are homozygous for each trait. So their all the offspring will be same as the parent.

So here a plant with purple flowers is allowed to self-pollinate, as generation after generation it produces purple flower, it means that it must be homozygous for purple color.

not always but somethings can be reproduced in a laboratory.