Answer:
Correct answer is Roosevelt's use of the Sherman Anti-trust Act .
Step-by-step explanation:
Roosevelt was not an important figure during WW1 as he finished his second term as president in 1909. That is why first and second option are not correct.
Third option is not correct because with this Act he tried to fight against business monopolies in the country.
Last option is not correct as Roosevelt was supportive of Imperialism.