at the current minnium required rate of return the net present value of an investment with 8 years useful life is negative 1, assuming the minium required rate of return and annual net cash flow projections stay the same, the investment would be

equally acceptable with a 7 to 9 year useful life

acceptable if the useful life can be increased to 9 years

acceptable if the useful ife is reduced to 7 years

equall acceptable with a 7-9 year useful life