If a firm has an operating income of $225,000, revenues of $900,000, and interest expense, other expenses, and taxes of $85,000, the net profit margin of the firm is __________.

25%

is equal to the operating income divided by revenue

is equal to the operating income plus interest, other expenses, and taxes divided by revenue

equal to the net difference between the operating income and interest expense, other expenses, and taxes divided by revenue