9-4. A special purpose NASA fuel cell requires an investment of $80,000 and has no MV at any time. Operating expenses in year k are given by C $10,000+$6,000(k- 1). Obsolescence is reflected in increased operating expenses and is equivalent to $4,000 per year -this expense has not been included in the equation for Ck. (Section 9.5) Determine the economic life of the fuel cell if i-0.25%. Possible answers: a. .1 year . 2 years 3 years 5 years