Jeff owned a warehouse he used in his business that decreased in value by $40,000 during the year and on December 31, 2018, it was worth $170,000, but he did not sell the warehouse. The effect on Jeff’s taxable income is:

a. capital loss equal to $40,000

b. ordinary loss equal to $20,000

c. deduction for AGI equal to $40,000

d. deduction from AGI equal to $20,000 subject to 10% of AGI floor

e. none of the above.