Differences among people begin with alleles, which can be caused by transpositions, deletions, or repetitions of base pairs, making some genes

a. polymorphic b. transmorphic c. multimorphic d. allelemorphic

The correct answer is option - polymorphic.

Explanation:

A discontinuous genetic variation leads to the foundation of various different alleles or forms of specific individuals among the members of a particular species.

Polymorphic can be explained as the trait which is attributed to 2 or more genes or alleles which are arisen by the transpositions, repetitions or deletion of base pairs. Such as skin color, height,  

Thus, the correct answer is - polymorphic.