Assume Walmart acquires a tract of land on January $1,2018,$ for $$100,000$ cash. On December $31,2018,$ the current market value of the land is $$150,000.$ On December $31,2019,$ the current market value of the land is $$120,000.$ The firm sells the land on December $31,2020,$ for $$180,000$ cash.

Required

Ignore income taxes. Indicate the effect on the balance sheet and income statement of the preceding information for $2018,2019,$ and $2020$ under each of the following valuation methods $($Parts a$$c$).$

Valuation of the land at acquisition cost until sale of the land $($Approach $1)$

Valuation of the land at current market value and including market value changes each year in net income $($Approach $2)$

Valuation of the land at current market value but including unrealized gains and losses in accumulated other comprehensive income until sale of the land $($Approach $3)$

Why is retained earnings on December $31,2020,$ equal to $$80,000$ in all three cases despite the reporting of different amounts of net income each year?