4. Using a 12% MARR, calculate the present worth of the costs for the two alternatives described below, based on the "outsider viewpoint" method, when the need for the equipment is expected to continue indefinitely. The present equipment could be sold now for $5,000, but in 3 years it will have no salvage value owing to radically improved equipment expected to be available then; it will cost $1,000 to remove the old equipment in 3 years. This alternative (A) has annual expenses of $3,900. A greatly improved version of the equipment which is to be introduced in 3 years will have annual operating costs of $1,900, a first cost of $10,000, and a salvage value of $2,000 at the end of its 3-year life. A presently available replacement has a price of $13,500 and a salvage value of $500 at the end of its 6-year economic life. This alternative (B) has operating costs of $3,000 per year