Which sentence describes an external conflict? roland must ride his bike through a monsoon to get home. roland will get kicked off the team if he gets overconfident. roland must practice every day if he wants to be picked first. roland is the protagonist of this short story.

As you know, an external conflict usually represents the idea of outside-forces  influence, and  sentence which accurately describes an external conflic is the first one :Roland must ride his bike through a monsoon to get home. You can see how external force opposes on the journey of the main hero.

Ibelieve it is entry b.