On March 12, Klein Company sold merchandise in the amount of $7,800 to Babson Company, with credit terms of 2/10,n/30. The cost of the items sold is $4,500. Klein uses the perpetual inventory system and the gross method of accounting for sales. On March 15, Babson returns some of the merchandise, which is not defective. The selling price of the returned merchandise is $600 and the cost of the merchandise returned is $350. The entry or entries that Klein must make on March 15 is