Detailed Answer
Answer (C) is correct. The carrying amount of the PPE account, net of accumulated depreciation, is increased by the cost of purchases and decreased by the carrying amount of items of PPE sold and depreciation. The net PPE decreased by the carrying amount of items sold, or $20,000 ($50,000 cost – $30,000 accumulated depreciation), and by the $10,000 of depreciation. If PPE still increased by $80,000, $110,000 ($30,000 total decrease + $80,000 increase) of equipment must have been purchased.