The right answer is D-chromosomes.
Chromosomes are visible only at the time of cell divisions (mitosis or meiosis). They essentially contain the molecules of A.D.N. carriers of genetic information and proteins such as histones that maintain the structure of chromosomes.
Each species contains a number of chromosomes of its own. In most sexually reproducing species, non-sexual cells (somatic cells) possess duplicate chromosomes, one of which is derived from the male gamete and the other from the female gamete. These species, individuals or cells are called diploids. Gametes that contain only one chromosome of each pair are called haploid.