Ann Torbert purchased a truck for $1 1,000 on January 1, 2005. The truck will have an estimated salvage value of

$1,000 at the end of 5 years. Using the units-of-activity method, the balance in accumulated depreciation at December 31. 2006, can be computed by the following formula:

a. ($11,000 -h Total estimated activity) X Units of activity for 2006.

b. ($10,000 * Total estimated activity) X Units of activity for 2006.

c. ($1 1,000 * Total estimated activity) X Units of activity for 2005 and 2006.

d. ($10,000 * Total estimated activity) X Units of activity for 2005 and 2006.