Ben purchased a personal residence for $70,000. The home was not depreciated. It had a fair market value of $90,000 when it was damaged from a fire due to him smoking in bed. The fair market value after the fire was $50,000 and insurance proceeds totaled $20,000. What is the net amount of casualty loss he can claim if his adjusted gross income is $100,000?
a. $0
b. $10,000
c. $9,900
d. $40,000