Give one reason to support your answer in (a).

Because the two CHROMATIDS of each chromosome have SEPARATED at the centromere and are being pulled by the contracting spindle fibres towards OPPOSITE POLES of the cell.

The reason must describe what is VISIBLE in the diagram, not what you remember about anaphase in general. Point to the separation at the centromere and the movement towards the poles.

THE DEFINING EVENT OF ANAPHASE is the splitting of the CENTROMERE. Until that moment the two chromatids are one chromosome; the instant it divides they become two independent chromosomes, and the cell briefly contains double the usual number.

The V or J shape of the moving chromosomes is itself evidence: the spindle fibre pulls at the centromere, so the arms trail behind like a towed object — which is why they bend.