Rasa examines the dossiers. One immediately jumps out as the frontrunner, but he figures he'll give each some thought.
Athena certainly appealed to Rasa's desire to understand the likely legendary beast that felled his father, and forced evolution seemed like a potential shortcut to gain some power. But in the end, he wanted to earn his own strength and he knew he wouldn't have the patience to study myths.
Lance...was not worth any thought whatsoever.
Ace held Rasa's attention for a bit. The trainer Rasa sought vengeance on was probably very high up the world rankings. But organized combat wasn't exactly Rasa's cup of tea, so he decided to pass.
That left Apollo, Rasa's initial choice. This man would provide Rasa with what he wanted and needed: tough training and the chance to gain powerful allies.
With that in mind, Rasa heads off to meet Apollo. "Let's see if you live up to your reputation, human."
Can we as pokemon speak to humans?