On each weekly spelling test, the students in Mrs. Ruiz's class record how they do in comparison to the week before.
For example, if they spell two more words correctly this week than last week, then they put a +2 in the corner of their
paper. If they spell two less words correctly this week than last week, then they put a -2 in the corner of their paper,
After collecting the papers, Mrs. Ruiz notices that the first four papers had the following marks:
Student A-1
Student B: 0
Student C-3
Student D:2

Which student's score changed the most from last week?

Student A
Student B
Student D
Student C