Answer:
✅ characterizes opposing viewpoints in a negative light ➡ "foolish optimist"
✅emphasizes the sadness and seriousness of the situation ➡ "grim problem of existence
✅encourages optimism and hope ➡ "not an unsolvable problem"
Explanation:
I have been able to match each excerpt from the passage with the statement that best describes its effect.
A "foolish optimist" actually characterizes opposing viewpoints in a negative light. He tends to be optimistic even in overwhelming negativity.
The "grim problem of existence" tells about how serious and disheartening the situation or condition is.
Their "not an unsolvable problem" denotes that there is hope and one is very optimistic for a solution.
Then best option would be B. Weakness
Conveys a message about life
