Final answer:
The egg and sperm nuclei are referred to as gametes, which are reproductive cells carrying half the number of chromosomes of body cells, to form a diploid zygote upon fertilization. Thus, the option c is the correct answer.
Step-by-step explanation:
The egg and sperm nuclei are also called gametes. These reproductive cells are significant for sexual reproduction, as they each carry half the number of chromosomes compared to normal somatic, or body cells. This haploid state, designated as 1n, is crucial because when an egg and a sperm unite during fertilization, they form a zygote, which is a diploid cell with two complete sets of chromosomes—one from each parent. In humans, this means the zygote will have 46 chromosomes, with 23 from the mother and 23 from the father.