The selected transactions below were completed by Cota Delivery Service during July: Indicate the effect of each transaction on the accounting equation by choosing the appropriate letter from the following list:

A. Increase in an asset, decrease in another asset.

B. Increase in an asset, increase in a liability.

C. Increase in an asset, increase in stockholders' equity.

D. Decrease in an asset, decrease in a liability.

E. Decrease in an asset, decrease in stockholders' equity.

3. Paid rent for October, $4,500.

6. Billed customers for delivery services on account, $58,000.

7. Paid creditors on account, $2,900.

8. Received cash from customers on account, $27,500.

9. Determined that the cost of supplies on hand was $300 and $8,600 of supplies had been used during the month.