Elkins Corporation uses the perpetual inventory and the gross method. On March 1, it purchased $50,000 of inventory, terms 2/10, n/30. On March 3, Elkins returned goods that cost $5,000. On March 9, Elkins paid the supplier. On March 9, Elkins should credit: purchase discounts for $1,000. O inventory for $1,000. purchase discounts for $900. inventory for $900.