A stream that is 3 wt% B and the 97 wt% C, and a stream that contains only A and B (5,300 kg/hr total), are fed to a column. Three product streams emerge: the overhead is 100% A. The bottom stream is 60 wt% B and 40 wt% C. The middle stream is 70 wt% A and the rest B and C and flows at 1,200 kg/hr. How many material balances can be written on the overall system?