6. An exam consists of 6 multiple-choice questions, with the following scoring rules: each person starts with 6 points, gets 4 points for each correct answer, loses 1 point for each wrong answer, and gets 0 points for not answering. Now, 51 students are taking the exam, so at least ( ) people have the same score.
(A) 3
(B) 4
(C) 5
(D) 6
【Answer】A
【Question Type】Combination: Drawer Principle
【Analysis】Let the number of correct answers be $x$, and the number of wrong answers be $y$, $x+y \leq 6$; when $x=6$, the score is 30 points;
when $x=5$, $y=0,1$, the corresponding scores are 26, 25;
when $x=4$, $y=0,1,2$, the corresponding scores are $22, 21, 20$;
when $x=3$, $y=0,1,2,3$, the corresponding scores are $18, 17, 16, 15$;
when $x=2$, $y=0,1,2,3,4$, the corresponding scores are $14, 13, 12, 11, 10$;
when $x=1$, $y=0,1,2,3,4,5$, the corresponding scores are $10, 9, 8, 7, 6, 5$;
when $x=0$, $y=0,1,2,3,4,5,6$, the corresponding scores are $6, 5, 4, 3, 2, 1, 0$;
In total, there are 25 possible scores, $51 \div 25=2 \cdots 1$, so at least $2+1=3$ people have the same score.