the answer is C but i am not sure how to solve for it.

35) Profitable Corp generated $2,000,000 in operating profits for the fiscal year just ended. Profitable has $4,000,000 of long-term debt with an interest rate of 10%, preferred stock with a 12% coupon, and paid $250,000 of dividends to its common stockholders. Profitable paid income taxes of $300,000. What is Profitable's corporate income tax rate? A. 21% B. 34% C) 18.75% D. 37.5% E. 15.25%