The chromosomal mutation in the zygote can be traced back to chromosome 6 in the egg cell. The option B is the right answer.
Step-by-step explanation:
The mutations in chromosome mostly occurs in the process of meiosis in germ cells i.e egg or sperm cells. The number of chromosomes in egg or sperm cells should be haploid so that on fertilization zygote is formed with diploid chromosomes.
Mutation in chromosome in meiosis results in extra number of chromosomes or structural defect in the chromosome. Chromosomal mutations also occur due to chemical agents or mutagens.
During cell division the homologous chromosomes are separated from sister chromatids, any abnormality at this stage causes unequal separation or non-disjunction of chromosomes. This is the case shown in chromosome 6 of the egg cell.
Such chromosomes leads to syndrome in the child as down syndrome or turner syndrome as the resulting child will have one extra chromosome in the child.
It can be seen in the diagram that zygote has one extra chromosome at chromosome number 6 which is abnormal.