CAYLEY 2020 Problem 19

A multiple choice test has 10 questions on it. Each question answered correctly is worth 5 points, each unanswered question is worth 1 point, and each question answered incorrectly is worth 0 points. How many of the integers between 30 and 50, inclusive, are not possible total scores?

Answer Choices
A. 2
B. 3
C. 4
D. 6
E. 5