On January 1, Celebrity Allures Inc. bought a new popcorn popper for one of their movie theaters. The popper cost $6,000. The expected life is 5 years with a salvage value of $500. The popper is expected to produce 50,000 buckets of popcorn over its life. In the first year, the popper produced 9,000 buckets of popcorn. In the second year, the popper produced 12,000 buckets of popcorn. What is the book value after the second year on the popcorn popper assuming units of output depreciation?

$2,310 $4,680 $6,000 $3,690