Swing Hard collected $15,000 from customers for lessons given in February.
b. Swing Hard sold a gift card for golf lessons for $150 cash in February.
c. Swing Hard received $4,000 from credit sales made to customers in January.
d. Swing Hard collects $2,250 in advance payments for golf lessons to start in June.
e. Swing Hard bills a customer $125 for golf lessons given between February 25 thru February 28. The bill is to be paid in March.

Which of these considered revenues to be calculated in the income statement?