Answer:
Option B.
Step-by-step explanation:
The line that reveals the contrast between Valentine and Proteus and develops the theme of the passage is:
B. Valentine had spoken many wise words to Proteus on the folly of being in love, but he had not been long in Milan before he was in just the same sad plight that he had cautioned his friend against.
((This line highlights the irony of Valentine's situation, as he finds himself in love despite warning Proteus about the foolishness of being in love. It contrasts Valentine's actions with his earlier words of caution, emphasizing the theme of the passage which explores the complexities and contradictions of love.))