Let M={5,6,7,8} and N={3,4,9,10}. Which one of the following functions is neither one-one nor onto?

• A. f={(5,3),(5,4),(6,4),(8,9)}
• B. f={(5,3),(6,4),(7,9),(8,10)}
• C. f={(5,4),(5,9),(6,3),(7,10),(8,10)}
• D. f={(6,4),(7,3),(7,9),(8,10)}