Which politician has a dual role in the US government; one is executive and one is legislative?

a. speaker of the house

c. justice

b. president

d. vice-president

D.) Vice-president because it does that.

It would be the "Vice President" who has a dual role in the US government; one is executive and one is legislative--since his role as Vice President is part of the Executive Branch, but the other role for this position is to "preside over the Senate" which is part of the legislative branch.