What is a difference in impairment accounting when comparing US GAAP to IFRS? Select one:

a. Financial assets must be reviewed for impairment at the end of each reporting period.

b. There is no need to test for impairment on held-for-trading investments since all gains and losses are regularly booked through income.

c. Impairments of debt securities relating to credit losses are recognized through income when incurred.

d. If the value of the investment recovers, such losses are reversed through income if they relate to debt instruments.