The following selected transactions were completed by Speedy Delivery Service during October:
1. Received cash from owner as additional investment, $30,000.
2. Purchased supplies for cash, $1,500.
3. Paid rent for October, $4,000.
4. Paid advertising expense, $2,500.
5. Received cash for providing delivery services, $18,750.
6. Billed customers for delivery services on account, $41,500.
7. Paid creditors on account, $6,000.
8. Received cash from customers on account, $26,200.
9. Paid cash to owner for personal use, $2,000.
Indicate the effect of each transaction on the accounting equation by listing the numbers identifying the transactions, (1) through (9), in a column and inserting at the right of each number 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 owner's equity.
d. Decrease in an asset, decrease in a liability.
e. Decrease in an asset, decrease in owner's equity.