Each of the following independent events requires a year-end adjusting entry. Show how each event and its related adjusting entry affect the accounting equation. Assume a December 31 closing date. The first event is recorded as an example. (Do not round intermediate calculations. Enter any decreases to account balances with a minus sign.)
a. Paid $7,100 cash in advance on April 1 for a one-year insurance policy.
b. Received an $16,620 cash advance for a contract to provide services in the future. The contract required a one-year commitment starting September 1.
c. Purchased $2,150 of supplies on account. At year's end, $210 of supplies remained on hand.
d. Paid $5,700 cash in advance on March 1 for a one-year lease on office space.