Answer:
Cost principle.
Explanation:
Cost or historical cost principle.
The assets, liabilities and equity must enter the accounting at their original purchase cost rather than current market value. This bulding, which is an asset was purchase for 500,000. Therefore, his cost is 500,000. It will be recorded at 500,000.
And will not increase for changes in the market value. Only at the moment of selling or disposal of the assets the accounting will recognzie a gain or loss.