Christian had brochures printed for a new business venture. Christian originally ordered 4 boxes of black-and-white brochures and 3 boxes of color brochures, which cost a total of $134. After those ran out, Christian spent $120 on 3 boxes of black-and-white brochures and 3 boxes of color brochures. Which system represents this situation?
a. x+y=134
x+y=120
b. 3x+3y=134
4x+3y=120
c. 4x+3y=134
3x+3y=120
d. 7xy=134
6xy=120