Windham Corporation has current assets of $480,000 and current liabilities of $600,000. Windham Corporation's current ratio would be increased by which of the following:

• refinancing a $180,000 long-term loan with short-term debt.

• the purchase of $180,000 of inventory on account.

• the payment of $180,000 of accounts payable.

• the collection of $180,000 of accounts receivable.