Final answer:
The passage suggests that optimism lies in how we react to challenges, supporting the idea that even in difficult times, there is room for happiness through optimism, which aligns with option B.
Step-by-step explanation:
The passage conveys a theme of optimism in the face of challenges and adversity. The best choice that matches this theme is that optimism allows for happiness even in bleak circumstances. This is reflected in the idea that while we may not be able to eliminate all difficulties, our reaction to challenges can be one of hopeful adaptation and seizing advantages even in tough times. Therefore, the correct answer is B) Optimism allows for happiness even in bleak circumstances.