Final answer:
Apollo might oppose supporting Achilles as this act could be seen as challenging preordained fate, which is often upheld by the gods in Greek mythology.
Step-by-step explanation:
When discussing why Apollo might say they shouldn't support Achilles and what he's doing, we must refer to the theme of fate in Greek mythology and literature. The most fitting answer from those provided would be, 'Because Achilles is challenging fate'. Greek heroes often confront or attempt to avoid their fates, with Achilles being no exception. With his mother attempting to make him invincible and the prophecy of his short life if he chooses the path of a warrior, Achilles' story is deeply interwoven with the concepts of destiny and the will of the gods. Hence, Apollo, as a god, might believe that supporting Achilles in his challenge to fate could be detrimental or futile because gods often represent the order of fate in mythology.