Chemical costs associated with a packed-bed flue gas incinerator (for odor control) have been decreasing uniformly for 5 years because of increases in efficiency. If the cost in year 1 was

$100,000 and it decreased by $5,000 per year through year 5, the present worth of the costs at 10% per year is closest to:

a. $344,800

b. $402,200

c. $485,700

d. $523,300