Riverbed Ltd. had beginning inventory of 52 units that cost $100 each. During September, the company purchased 203 units on account at $100 each, returned 9 units for credit, and sold 151 units at $202 each on account. Journalize the September transactions, assuming that Riverbed Ltd. uses a perpetual inventory system. (Credit account titles are automatically indented when the amount is entered. Do not indent manually. If no entry is required, select "No Entry" for the account titles and enter O for the amounts.) Account Titles and Explanation Debit Credit (To record purchase on account)