Hi Santhosh,
The missing key word is Control here
Remember this - All changes to the scope baseline must be monitored and controlled, and in Control Scope you are comparing the actual result with the baseline to determine if the variance is within the threshold amount or if corrective or preventive action is appropriate (PMBOK 6 pg 169-170)
To answer your question:
A) If proper Integrated Change Control procedures are performed, then the change is considered controlled and therefore not a scope creep
D) Again, if the variance is under control and within the threshold, it may prove beneficial to the project (ex. Less work but better result)