18 (1 point) To compute the present value of the cash flow stream in two steps: First, compute the present value of each cash flow. Then ___________ the present values. Question 18 options: Combine Separate None of the above Question 19 (1 point) Timeline for a perpetuity : The first cash flow arrives at the end of the _________ period. Question 19 options: Zero First Two None of the above Question 20 (1 point) A stream of equal cash flows that occur at regular intervals and last forever is known as _______________. Question 20 options: A) None of the above B) Annuities C) Perpetuity