10. Cedar Hospital has a marketable equity securities portfolio that is included appropriately in noncurrent assets in unrestricted funds. The portfolio has an aggregate cost of $300,000. It had an...

10. Cedar Hospital has a marketable equity securities portfolio that is included appropriately in noncurrent assets in unrestricted funds. The portfolio has an aggregate cost of $300,000. It had an aggregate fair value of $250,000 at the end of 2019 and $290,000 at the end of 2020. If the portfolio was reported properly in the balance sheet at the end of 2020, the change in the valuation allowance at the end of 2020 should be

a. $0.

b. a decrease of $40,000.

c. an increase of $40,000.

d. an increase of $50,000