Final answer:
Normal human gametes, which are sperm and egg cells, carry 23 chromosomes. This includes 22 autosomes and a single sex chromosome, which can be either X or Y in males (XY) and two X chromosomes in females (XX).
Step-by-step explanation:
Normal human gametes carry 23 chromosomes. Among the given options, (a) 23 is the correct answer. Human cells typically contain 23 pairs of chromosomes, totaling 46, but gametes, which are the reproductive cells such as sperm and egg cells, contain only one set of these chromosomes. This means that each gamete has 22 autosomes and one sex chromosome, for a total of 23 chromosomes. The autosomes are the first 22 pairs of chromosomes that are identical in both males and females, while the sex chromosomes differ between the genders. Females have two X chromosomes, and males have one X and one Y chromosome.