Correct Answer: whereas

Solution : The most appropriate word is the second option.

Explanation : In this sentence, there is a clear contrast between the wise, who try to improve themselves, and the fools, who keep blaming their luck. The conjunction whereas is used to introduce a contrast or difference between two clauses. It is grammatically correct and conveys the intended meaning.

So, the correct sentence would be: "The wise try to improve themselves, whereas the fools keep blaming their luck."