What is the present value of the following series of cash flows discounted at 12 percent: $40,000 now, $50,000 at the end of the first year; $0 at the end of the second year; $60,000 at the end of the third year; and $70,000 at the end of the fourth year? a. $165,857. b. $167,534. c. $168,555. d. $171,836.