We know he is paid $4,200, and we also know he makes 2% on everything over $50,000. He made $60,000 which is $10,000 over the minimum, so he made 2% of $10,000. Multiply 0.02 times 10,000 and you get 200. We then add 200 to his base pay of 4,200 and we get 4,400.
The answer is B- $4,400.
Hope that helps!