A purchaser pays 500,000 for a mine which will be exhausted at the end of 30 years. Find the required level annual revenue (received at the end of each year) in order for the purchaser to receive a 7% annual return on his investment if he can recover his principal in a sinking fund earning 4% per year. (A) 37,400 (B) 37,594 (C) 39,130 (D) 39,200 (E) 39,368