Final answer:
The adjusting entry for depreciation expense at the end of year 1 using the straight-line method is B. $1,200 for both Depreciation Expense and Accumulated Depreciation.
Step-by-step explanation:
The adjusting entry for depreciation expense at the end of year 1 using the straight-line method is option B: Depreciation Expense - Equipment 1,200 and Accumulated Depreciation - Equipment 1,200.
The straight-line method allocates the cost of an asset evenly over its useful life.
In this case, the equipment has a total cost of $3,600 and a three-year life, so the annual depreciation expense would be $3,600 divided by 3 years which equals $1,200.
Accumulated Depreciation represents the total depreciation recorded over the years, and at the end of year 1, it would also be $1,200.