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: HEAVY MACHINERY 
Clue: By definition it's a machine that gives a surface an even degree of slope
grader

Category: THE 1970s 
Clue: In 1977 Bank of America changed the name of its Bank Americard to this 4-letter word
visa

Category: CHOOSE A "CIDE" 
Clue: Final act of playwrights Seneca & von Kleist

suicide