According to double-entry accounting, which of the following is a correct statement regarding transactions?
a) Each transaction must increase an asset and a liability.
b) Purchasing supplies on account is shown by an increase on the left side of the T- account called Accounts Payable.
c) Any time a company increases its revenue, the owner's equity is also increased.
d) Entering an amount on the left side of a T-account increases the balance in that account.