The best cell division stage to observe the shape, size and number of chromosome is

The best cell division stage to observe the shape, size and number of chromosomes is the metaphase. The chromosomes appear shortest and thickest during this phase and are arranged at the equator and form an apparent plate called as equatorial or metaphase plate thus readily visible. Therefore, this phase is often chosen for karyotyping and for chromosome analysis. So, the correct answer is option A.