A bulk materials hauler purchased a used dump truck for %50,000. The operating cost was %5,000 per year, with average revenues of %7,500 per year. After 24 years, the truck was sold for %11,000. The rate of return was closest to;

a)6.6% per year

b)2.6% per year

c)4.6% per year

d)7.6% per year