PLZ ANSWER MY QUESTION ASAP Which option explains Cynthia’s exhaustion in the following scenario?

Cynthia is training for her first swimming race, and she is noticing the more she gains speed, the more tired she becomes.

The faster Cynthia swims, the more energy she must exert to overcome drag.

Cynthia uses all her energy to get to her fastest speed.

Cynthia needs to work on her stamina to make it through the race.

Cynthia’s arms and legs become heavier the longer the race goes on.