A, B, C are correct. D may be a trick question (I believe it needs to be removed to be controlled), E may not be for all cases where there is pre-existing attachment loss below CEJ and periodontium has been restored to health.
For patients had periodontal disease, and now doing a review:
A: if the bleeding on probing is <10% is also considered to be stable
C: if pocket depth </= 4mm is also considered to be stable (and there should be no bleeding on probing no 4mm sites)
E: has to be case by case, depending what the patient starts off
Reference: new AAP 2018 periodontal classification paper