Gems Inc has the following account balances (in thousands): 2016 2015 Buildings 1,000 720 Accum. Dep-buildings (330 (220) Machinery 450 380 Accum. Dep - machinery (130 )(100) There was a building addition of $280 thousand. There was a machinery purchased for $90 thousand. Also, machines with an original cost of $20 thousand and related accumulated depreciation of $10 thousand was sold for $15 thousand. What is the depreciation expense to be included in the operating section? a. $110 b. $160 C. $150 d. $140