Final answer:
The sale of land for cash at its cost by Hansen Enterprises affects the assets by changing their composition, but the overall value remains the same. There is no impact on retained earnings, common stock, or liabilities. Thus, the correct option is D.
Step-by-step explanation:
When Hansen Enterprises sold land for cash at an amount equal to its cost, the only accounts that would be affected are assets.
Since the land, an asset, is exchanged for cash, another asset, there would be no change in the total amount of assets, just a change in the composition of assets.
There would be no effect on retained earnings, common stock, or liabilities since no profit or loss was realized on the sale, no new stock was issued, and no debts were created or settled. Thus, the correct option is D.