A couple's genetic counselor shows them magnified photographs of each parent's chromosomes arranged on a chart according to size and structure.What is this chart called?

A) Allele typing
B) Phenotype
C) Gamete analysis
D) Karyotype

The chart of magnified photographs of each parent's chromosomes arranged according to size and structure is called a karyotype. A karyotype is a visual representation of an individual's chromosomes, which can be used to identify genetic abnormalities or disorders. This tool is often used in genetic counseling to help couples understand any potential risks of passing on genetic mutations or disorders to their children.