B. If indicators suggest that impairment may have been reversed, either wholly or partly, the recoverable amount has to be re-estimated

Under IAS 36 Impairment of Assets, once an impairment loss is recognized, it is not reversed even if the underlying circumstances change. However, if there are indications that the impairment loss might no longer exist or has reduced, the entity is required to re-estimate the recoverable amount of the asset. According to IAS 36, impairment losses are not normally reversed, but the standard does not explicitly prohibit the reversal of impairment losses in certain circumstances where the underlying circumstances have significantly changed. Goodwill impairment, in particular, is not reversible under IAS 36. Therefore, options A and C are incorrect, and option D is false because IAS 36 does not permit the reversal of goodwill impairment.