Sister chromatids are best described as two dna molecules that have:
a. different genes in a different order with different alleles.
b. the same genes in the same order with different alleles.
c. different genes in the same order with different alleles.
d. the same genes in the same order with the same alleles.

The correct answer is d. the same genes in the same order with the same alleles.

Explanation:

Sister chromatids are produced by the replication of a single chromosome so sister chromatids are double copies of single chromosome, therefore, sister chromatids are identical to each other which means the same sequence of genes are present in the same order with the same alleles.

Sister chromatids are produced during the synthesis phase of the cell cycle and joined together at the centromere. They are separated in mitotic division in the case of somatic cells or in meiosis II in the case of germ cells. During cell division, these sister chromatids are separated into daughter cells. So the right answer is d.