A negative residual is far more often an error than a genuine bargain, so the standard requires the search before the recognition.
That was the approach under earlier guidance. Current guidance recognizes the excess as a gain rather than distorting asset measurements.
There is no deferral. The gain is recognized on the acquisition date.
That is what the reassessment tests. Once it finds no error, the standard requires the gain rather than assuming one must exist.
Answer: a
Choice a. Reassess first, then recognize any remaining excess in earnings on the acquisition date.