To what extent was U.S. foreign policy from 1890 to 1914 guided by economic motives?
Whenever you get a question like this, the answer is usually "to some extent." In other words, teachers only ask this kind of question when the factor in the question is part of the story but not all of it.
In this case, economics was part of the story. It drove our desire to have an "Open Door" in China. It helped to cause our desire to take the Philippines and to control Cuba. It helped cause us to do the "dollar diplomacy" of Taft's time in office.
However, it was not all that there was to our foreign policy. Foreign policy was also affected by such things as military concerns (Panama Canal, taking the Philippines, taking Hawaii) and by a desire to "civilize" countries that were "backwards" (the Philippines in particular).
Thus, economic concerns were part of what drove American foreign policy, but were not the only factor involved.