can someone explain this and let me know the correct answer

Incorrect Question 4 0/2 pts Determine the book value for the Building. Williams Consulting Balance Sheet December 31, 2012 Current Assets Cash Accounts receivable Supplies Total current assets 22,800 41,200 4,000 68,000 43,000 Property. Plant and Equipment Equipment Less: Accumulated Depreciation Building Less: Accumulated Depreciation Total Property. Plant, and Equipment Total Assets 48,000 5,000 520,000 20,000 500,000 543,000 611,000 Liabilities Current Liabilities Accounts payable Uneamed Revenue Total Liabilities 30,000 21,000 51,000 Stockholder's Equity Common stock Retained earnings 310,000 250,000 Total Property, Plant, and Equipment 543,000 611,000 Total Assets Liabilities Current Liabilities Accounts payable Unearned Revenue Total Liabilities 30,000 21,000 51,000 Stockholder's Equity Common stock Retained earnings Total stockholders' equity Total liabilities and stockholders' equity 310,000 250,000 560,000 611,000 $20,000 $520,000 $543,000 Incorrect. Book Value - Cost - Accumulated Depreciation $500,000