Company B:15000× 6+1200+2400+3600+4800+6000 =108000 (yuan);
Company C: 2000× 36+100× (24+23+22+…+3+2+1) = 72000+100× 300 =102000 (.
Thus, Company B is superior.
A: It is better for Zhang Hua to go to Company B because he gets more money from Company B than other companies.