While writing a persuasive piece which appeal should you use to evoke emotion in your audience

You should use Pathos to evoke emotion in your audience.

Explanation:

There are three well-known forms of persuasion first introduced by Aristotle: Ethos, Logos, and Pathos.

Ethos happens when the speaker appeals to ethics. For that reason, how effective this device will be depends on how credible the speaker is. If the speaker is a role model or, for instance, an expert on the matter, listeners are more likely to trust his argument.

Logos appeals to logic and its efficacy relies on structure and evidence. Thus, the speaker must walk the audience through the logical path to the conclusion they must reach.

Finally, Pathos is an emotional argument, an appeal to the audience's emotions. It targets shared feelings and cultural values with the goal of having the listener relate to what is being said.  Empathy, pity, comprehension, even anger can all be triggered by an effective argument relying on Pathos.

adding more details about the struggle rainsford experiences as he swims to the shore

the first, third, and last sentences are correct for plato.