Which of the following is a method that geneticists use to determine if an individual has chromosome abnormalities?

The correct answer would be karyotype of an individual.

Karyotype is the diagrammatic representation of the number and appearance of the chromosomes of an organism.

It determines the count of the chromosomes, their length, banding patterns, position of centromeres, difference between the sex chromosomes and other physical characteristics if present.

It helps in determining the presence of any chromosomal abnormalities in an organism.

For example, Turner syndrome (45, XO), Klinfelter syndrome (47, XXY), Down syndrome (trisomy of chromosome 21) et cetera .

the answer is d. chordata