1- Suppose that, in a merchandising firm, the opening balances of total assets and total equity are 60.000 TL and 38.000 TL, respectively. During the period, the following FIVE transactions are recorded: 

(a) 13.000 TL worth of inventory is purchased on account. 

(b) A buyer party pays prior period's sales invoice of 6.000 TL. 

(c) 9.000 TL of the inventories are sold on cash at a price of 12.000 TL. The firm employs perpetual inventory system. 

(d) A depreciation amount of 2.000 TL is charged for the headquarters building. 

(e) A payment of 4.000 TL is made to the supplier for the inventory purchasing transaction. At the end of the period, interestingly, the ending balances of total assets and total liabilities are 72.000 TL and 30.000 TL, respectively. The accountant of the firm has realized that one transaction is MISSING. In other words, there should be a SIXTH transaction. Which one of the following might be that transaction?

a- 3.000 TL of sales revenue is generated, where 2.000 TL is paid immediately and the remainder is on account.

b- An owner contributes 3.000 TL in cash that settles his 1.000 TL of payable to the company.

c- The firm performs a service for 3.000 TL in consideration for 2.000 TL cash while the remainder is deducted from the creditors balance.

d- An inventory of 2.000 TL is sold at a price of 5.000, where the whole payment is made in cash.