Choice "A" is correct. Under IFRS, impairment exists when the carrying value of a fixed asset exceeds the fixed asset's recoverable amount. The recoverable amount is the greater of the asset's fair value less costs to sell and the asset's value in use (present value of future cash flows). In this problem, the fair value less costs to sell of $105,000 exceeds the value in use of $100,000, so the recoverable amount is $105,000. The carrying value of $120,000 exceeds the recoverable amount of $105,000, so an impairment loss must be recorded:

Choice "d" is incorrect. The carrying value of $120,000 exceeds the $105,000 recoverable amount, so an impairment loss must be recorded. Choice "b" is incorrect. The impairment loss is not the difference between the carrying value and the undiscounted expected future cash flows.
Choice "c" is incorrect. Under IFRS, impairment exists when the carrying value of a fixed asset exceeds the fixed asset's recoverable amount. The recoverable amount is the greater of the asset's fair value less costs to sell and the asset's value in use (present value of future cash flows). In this problem, the fair value less costs to sell of $105,000 exceeds the value in use of $100,000, so the recoverable amount is $105,000, not $100,000, and the impairment loss is $15,000, not $20,000.