On its December 31, 2017 balance sheet, Free Company appropriately reported a $10,000 debit balance in its Fair Value Adjustment (available-for-sale) account. There was no change during 2018 in the composition of Frees portfolio of debt investments held as available-for-sale securities. The following information pertains to that portfolio: Security Cost Fair value at 12/31/18 X $125,000 $160,000 Y 100,000 85,000 Z 175,000 125,000 $400,000 $370,000 What is the balance of the AOCI account due to debt investments in Stockholder's Equity at 12/3/12018?

Select one: a. $30,000 credit b. $10,000 credit c. $0 d. $40,000 credit e. $10,000 debit f. $30,000 debit g. $40,000 debit