Make laws is your best answer.
All of them hold significant power (& opinions can vary), however, in my opinion, laws hold the greatest weight. Through making of laws, they may make businesses change the way they market (which encompasses regulating commerce) & do business transactions. They can make laws that can limit who can be chosen to be Chief Justice (choice B) as well as hold the action of affirming or negating the choice of the president. They can declare war (when the president asks them too (Choice C), and usually their right to it is not cut out (except for the time for the Vietnam War). They can impose and collect taxes (Choice D), and as they are the Congress, they are made to make laws (Choice E).
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