18) During the year, Greta's mountain cabin was almost completely destroyed by a fire started in her kitchen. She had adjusted gross income of $110,000 in 2020 and related data with respect to the cabin follows: Cost basis: $ 121,000 Value before casualty: $ 155,000 Value after casualty: $ 15,000 Greta was partially insured for the loss and in 2020 she received a $100,000 insurance settlement. What is Greta's allowable casualty loss deduction for 2020? A) $0. B) $9,900 C) $20,000. D) $35,900