Question

which is the most effective thesis statement?
fdr was the greatest president because he had a huge impact on history.
fdr was the greatest president because he brought about many positive changes.
fdr was the greatest president because he served four terms.
fdr was the greatest president because he established unprecedented measures that helped end the great depression.

Explanation:

An effective thesis statement needs a specific, arguable reason. The first option's "huge impact" is vague. The second's "many positive changes" is also vague. The third's "served four terms" is a fact but not a strong reason for being "greatest" (term length doesn't equate to greatness). The fourth option ("FDR was the greatest president because he established unprecedented measures that helped end the Great Depression") gives a specific, historically significant action (New Deal - type measures to end the Depression) as the reason, making it clear and supportable.

Answer:

The bottom - left statement: "FDR was the greatest president because he established unprecedented measures that helped end the Great Depression."