For how many unique pairs of nonnegative integers {a, b} is the equation a^2 - b^2 = 99 true?
Choose the correct choice.
A) 1  B) 3  C) 5  D) 7  E) 9

Rationale: "answer c ( a + b ) ( a - b ) = 99 3 cases for ( a + b ) , ( a - b ) 99 , 1 33 , 3 11 , 9 answer b"
Answer: B