The answer is Karyotype. By definition, the karyotype is a test that looks at the shape, size, and number of a person's chromosomes.
The other options are incorrect because:
Diploid means having two complete sets of chromosomes from each of the parents.
Homologous could be a gene that is inherited by a common ancestor.
Klinefelter refers to a genetic condition where a boy is born with an extra X chromosome.
