Homer Nerdhoff Has Just Invented a New Cheese Grater

Multiple Choice

Homer Nerdhoff has just invented a new cheese grater. He has been travelling around the country exploring marketing opportunities, and discovers that Martin Fitzhugh has for the past three years been selling the grater which he developed, using the same process, at his fine food store in Halifax. Homer hopes that by patenting his grater, he can stop Martin from selling his. Martin sees the danger, and decides to also apply for a patent. Which of the following is true?

A) Whoever registers his patent first will obtain the exclusive right to use it.
B) Homer cannot obtain a patent because his invention was already known and used by Martin.
C) Martin cannot obtain a patent because his invention has already been on sale for the past three years.
D) Homer cannot obtain a patent; Martin can
E) Both B and C