On January 1, 2019, Mango Company Purchased a New Truck

On January 1, 2019, Mango Company purchased a new truck for $88,200. Its estimated useful life is seven years or 200,000 miles. The truck's expected salvage value is $4,200. During 2019, the truck was driven 20,000 miles.
Assuming units-of-production depreciation, 2019 depreciation expense is:

A) $10,584
B) $12,600
C) $ 8,400
D) $12,000