In 2018, Martin Corp. acquired Glynco and recorded goodwill of $45 million. Martin considers Glynco a separate reporting unit. By the end of 2021, the net assets (including goodwill) of Glynco are $324 million and its estimated fair value is $260 million. The amount of the impairment loss that Martin would record for goodwill at the end of 2021 is:

a. $0

b. $ 60 million

c. $ 45 million

d. $ 15 million