The answer is C: "Why do you sigh when I splash in a puddle?"
The prepositional phrase is "along the beach"
along = preposition
the beach = object of the preposition
Helmholtz is a guy with an enormous amount of qualities. He is confident, good-looking, charming, well-liked and artistic. Although he is not completely at home in this new society, he is successful within it, and because of this, he is likely to be a static character.
Helmholtz is a kindred spirit to Bernard because both of them feel constrained by this world order. While Bernard is unable to adapt to this system because of his "weakness," Helmholtz is unable to adapt because of the superficiality of their pursuits.
Helmholtz secret ambition is to create art that is passionate, intense and emotional, such as Othello. However, there are no topics like that in the new world, and coming up with them is impossible from someone in that society. Helmholtz, however, holds unto the idea of writing something like that, and the closest he can get to is writing about the weather.
What bothers Helmholtz the most about his friend is how difficult Bernard finds it to fit into society, unlike himself. He finds this embarrasing.
