Detailed Answer
Correct answer: (C)
$122,500.
[The depreciation for 2009 and 2010 was 2 x [($650,000 - 10,000) ÷ 8] = $160,000. This leaves a book value of $490,000 (i.e., $650,000 - 160,000). The revised life is 6 years and 2 have passed so that the new depreciation would be based on 4 remaining years = $122,500 (i.e., $490,000 ÷ 4).]