Answer and Explanation:
The computation is shown below:
Years      Straight line       Units of production
Year 1 ($90,000 - $5,000 ÷ 5)   1,600 × 8.5 = $13,600
          = $17,000
Year 2        $17,000            2200 × 8.5 = $18,700
Year 3        $17,000            2400 × 8.5 = $20400
Year 4        $17,000            1,800 × 8.5 = $15,300
Year 5        $17,000             2000 × 8.5 = $17,000
Total         $85,000            $85,000
The 8.5 come from
= ($90,000 - $5,000) ÷ (10,000 hours)
= 8.5
hence, the units of production would be most appropriate