In which three situations is incomplete recovery required？（） A: AAfter a shutdown abort. B: BWhen recovering to an SCN. C: CWhen recovering until a specific time. D: DWhen a required archived log is missing.

Identify two situations in which the block header grows in a data block. （） A: Awhen row directories need more row entries B: Bwhen there is row migration in the data block C: Cwhen there is an increase in the PCTFREE value for the data block D: Dwhen more transaction slots are required than are initially configured