You will be given a trivia clue, and the category it belongs to. You should answer with the best answer that belongs in the category and is described by the clue. For simplicity, answers should be in all lower cased letters.

Category: THE TITANIC
Clue: When the RMS Titanic sank in 1912, its cargo included more than 7 million pieces of this, in some 3,400 sacks
mail

Category: NEWSMAKERS
Clue: In April 2005, during his first 2 days on the job, he received more than 56,000 e-mails
pope benedict xvi

Category: U.S. TRADE
Clue: It's the country from which the U.S. imports the most oil
canada