Respuesta :
Answer: Ethos.
Explanation: there are three main rhetorical strategies when giving an argument in a speech or in a text, they are pathos, logos and ethos. Pathos is appealing to the audience's emotions, logos consists in appealing to the audience's logic, and ethos is appealing to the audience's ethics. In the given excerpt from Kennedy's speech, we can see an example of Ethos, because he is using his position as president (which gives him credibility) to convince the audience.