Which number below best represents a positive charge of 1,350?
A. -1,250
B. 1,350
C. -1,350
D. 1,250

The first one, i believe, would be correct. all the others have one thing in common, and that's that they have repeating numbers. in the second one, x and y have repeating 6's and 3's, and in the third, x and y have repeating 6's as well. in the last one, there are repeating 3's. the first one has no repeating numbers.

Set up a system of equations