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.

Which female had a hit in 2011 Hold It Against Me?
britney spears

In the Shakespeare play 'Macbeth', which character carries Macbeth's head on stage?
macduff

What Greek letter is used to denote the ratio of the circumference of a circle to its diameter?
pi