In which phase of cell division do the chromosomes split and move towards the poles?

The morphology of chromosomes is best observed during which stage of cell division?

In which phase of mitosis do the chromatids of each chromosome separate from each other?

In which phase of cell division can chromosomes be counted most easily?

At which stage of mitosis do chromosomes start separating?

$A$: The complete disintegration of the nuclear envelope marks the start of metaphase.
$R$: Chromosomes are distinct with two chromatids at this stage.