The number of pair of sex chromosomes in the zygote of humans is
(a) One
(b) Two
(c) Three
(d) Four

Hint: The chromosomes were named for their unique properties by early researchers. It is one of the two sex-determining chromosomes in many organisms and found in both males and females. It is also part of the XY sex-determination system and the XO sex-determination system.

Complete answer
Every cell in the human body consists of 23 pairs of chromosomes i.e a total of 46 numbers of chromosomes where half of the chromosomes come from the mother while the other half comes from the father. A zygote is formed when the mother's egg fuses with the father's sperm and a zygote after multiple divisions forms into a baby. Humans have 23 sets of chromosomes of which 22 are the autosomes and 23rd are the sex chromosomes. Most of the observable features of organisms that are controlled by the genes on the chromosomes are the sex-linked characters that determine the organism's sex.
A pair of sex chromosomes are present in each individual. One is inherited from each parent. Females have XX chromosomes and the males have XY chromosomes with 44 autosomes in both sexes. Both male and female genders are characterized by the genes present on the X-chromosome, Therefore, it is called criss-cross heredity but in males, genes are present on the Y-chromosomes. The sex chromosomes are those chromosomes that determine the gender of the child. When the sperm contains X chromosomes and fuses with the female (X) chromosome then a daughter will be born while when the sperm contains the Y chromosome and then fuses with the female (X) chromosome then a son will be born.
Autosomes are a large number of genes, performing unique functions in the organism cells are found in an autosome which is one of the 22 number pairs of chromosomes that are carried by most of us in almost all of the cells of our body.

So, the correct answer is ‘one’.

Note:
In humans, approximately 20 sex-linked characters are found on the X-chromosomes. A sex-linked trait i.e of the X chromosomes is not received by the son from his father whereas a father can pass the same sex-linked traits to his daughter only. Sex-linked characters are controlled by the genes on the chromosomes is an observable feature of an organism that determining the organism's sex.