instruction:
Given an trivia question precisely answer the question with a word/phrase/name. External resources such as Wikipedia could be used to obtain the facts.
question:
Which is the penultimate letter of the Greek alphabet?
answer:
psi


question:
Although courted by his political opponent, Stephen Douglas, Mary Todd chose to marry which future American president?
answer:
abraham lincoln


question:
Which US city is served by McCarran Airport?
answer:

las vegas