SVEN WROTE FIVE DIFFERENT ONE-DIGIT POSITIVE INTEGERS ON A BLACKBO...

10. Sven wrote five different one-digit positive integers on a blackboard. He discovered that no sum of any

two numbers is equal to 10. Which of the following numbers did Sven definitely write on the

blackboard?

(A) 1 (B) 2 (C) 3 (D) 4 (E) 5

Part B: Each correct answer is worth 4 points