Sister chromatids present during mitosis are
a. duplicated chromosomes.
b. identical copies.
c. separated during mitosis.
d. made during the s phase.
e. all of the above.

The correct answer is e. All of the above.

Explanation:

Sister chromatids are made during the synthesis phase of the cell cycle. In the synthesis phase, the homologous chromosomes get replicated and sister chromatids are produced so they are produced by duplication of chromosomes.  

As sister chromatids are produced by replication, therefore, they are identical copies of parent chromosomes. These sister chromatids are joined to each other at centromere. They get separated during the anaphase of mitosis and moves to the opposite pole.

Therefore the right answer is e.