In this task, you're given an open-domain question. Your task is to provide an answer to the given question. There is only one unique answer for each question. Your answer should be short, and refer to an entity, date, number, etc. Do not put your answer in the context of a sentence.

The most important mineral product of northern chile is?
copper

Who played keyboard on the beatles rooftop concert?
Billy Preston

When did the addams family first air on tv?

September 18, 1964