Given a factoid/trivia type question, generate the topic of the question. The topic is the entity the question talks about.

In America, as what was Bill Shoemaker famous?
bill shoemaker

In what story of Arthur C. Clarke do Tibetan monks seek to list all the names of God as they believe He will bring the Universe to an end once this is done?
arthur c. clarke

Which of the alkali metals, with the atomic number 19 is missing from - Lithium, Sodium, Rubidium, Caesium and Francium?

alkali metal