6. (5 Marks) For each of the following cases, determine whether the one-year principle would apply. a. c. A defender has been in use for seven years and has negligible salvage value. Operating costs are $400 per year for electricity. Once every five years it is overhauled at a cost of $1000. b. A defender has been in use for seven years and has negligible salvage value. Operating costs are $400 per year for electricity. Once a year it is overhauled at a cost of $1000. A defender has been in use for two years and has negligible salvage value. Operating costs are $400 per year for electricity. Once a year it is overhauled at a cost of $1000. d. A defender has been in use for seven years and has a current salvage value of $4000. Its value one year from now is estimated to be $4000. Operating costs are $400 per year for electricity. Once a year it is overhauled at a cost of $1000. A defender has been in use for seven years and has a current salvage value of $4000. Its value one year from now is estimated to be $2000. Operating costs are $400 per year for electricity. Once a year it is overhauled at a cost of $1000. e