I would say b and c, since unfasten and clench are basically antonyms and those answers both have antonyms
At first glance, the passage seems like an appeal to ethos because of the name dropping. However, if one looks at the question that follows the statement, you can clearly see that it is an appeal to logos. As it persuades the audience to use their logic to come up with the answer to the question.
Answer:
A because skeptic is like skeptical so not fully trusting someone or something
