Answer:
The letter A is the answer.
Step-by-step explanation:
A paradox is an apparently true statement that leads to a logical contradiction, or a situation that contradicts common intuition. In the case of this excerpt, the speaker says that although he is satisfied to become a pianist, sometimes he feels dissatisfied because in fact he wanted to play the guitar. So we can conclude that the role of the paradox in this passage shows that you can feel satisfaction and dissatisfaction at the same time.