16. The length of time required for an investment to generate cash flows sufficient to recover its initial cost is the: A) Payback period. B) Internal rate of return. C) Pay as you go D) NPV duration E) None of the above 17. The payback rule can be best stated as: A) An investment is acceptable if its calculated payback period is less than or equal to some pre-specified number of years. B) An investment should be accepted if the payback is positive and rejected if it is negative. C) An investment should be rejected if the payback is positive and accepted if it is negative. D) An investment is acceptable if its calculated payback period is greater than some pre- specified number of years