In 2002, Roma was a schoolteacher and earned $40,000. But she enjoys creating cartoons, so at the beginning of 2003, Roma quit teaching and set to work as a cartoonist. She stopped renting out her basement for $5,000 a year and began to use it as her office. She used $5,000 from her savings account to buy a new computer, and she leased a printer for $150 a year. During 2003, Roma paid $1,250 for paper, utilities, and postage; the bank paid 5 percent a year on savings account balances; and Roma sold $50,000 of cartoons. Normal profit is $3,000 a year. At the end of 2003, Roma was offered $4,000 for her computer. For 2003, find out Roma's

1a. Explicit costs.
1b. Implicit costs.
1c. Economic profit.