Chromosomal morphology (structure) is best observed at
morphology is best observed at metaphase. Metaphase is a stage of
mitosis in the cell cycle in which chromosomes are at their most
condensed and coiled stage. These chromosomes, carrying genetic
information, align in the equator of the cell before being separated
into each of the two daughter cells. The structure of chromosomes is
quite clear at this phase of the cell cycle. So, the correct answer is 'Metaphase'.