William, a cash-basis sole proprietor, had the following receipts and disbursements for 2021: Gross receipts $ 60,000 Cost of sales 30,000 Other operating expenses 6,000 Medical expenses 600 for 2021, what amount should William report as net earnings from self-employment? Question options: a) $ 30,000 b) $ 24,000 c) $ 24,600 d) $ 23,400 e) None of the above