Answer:
I looked it up and hope this is correct but I think it's B.
The correct answer should be A. Whomever.
This is because this can be paraphrased as "the instructor has picked him" not "the instructor has picked he". Him corresponds to whomever while he corresponds to whoever.
By using figurative language
In 1920, American voters elected a President who promised <u>to increase the U.S. role in world affairs.</u>
The punctuation is correct if that is how how the statement started and ended.
