Brian invested $4,800 and borrowed $4,800 to purchase shares in a large retailing company. At the time of his investment, the stocks were selling for $58 a share. a. If Brian paid a $34 commission, how many shares could he buy if he used only his own money and did not use margin? (Round your answer DOWN to the nearest whole share.) Number of shares b. If Brian paid a $55 commission, how many shares could he buy if he used his $4,800 and borrowed $4,800 on margin to buy these stocks? (Round your answer DOWN to the nearest whole share.) Number of shares c. Assume Brian did use margin and his money, paid a $80 commission to buy, and paid $160 in interest and commission to sell his stocks. How much profit did he make on this investment if he sold the stocks for $61 per share? (Round the number of shares DOWN to the nearest whole number. Omit the "$" sign in your response.) Total profit after commissions