I have gall bladder polyp with size 2.75mm *1.9mm....

is gall bladder polyp in your case harmful ?
according to the current size , its doesnt appear to be harmful 
will it grow ?
gall bladder polyp may grow , but its also not indeed 
what is the current treatment options in your case :
- no symptoms :
1. preservation and no need for treatment 
2. redo US test after 12 months to check if there is any growth,  if so , surgical removal is needed 
- with symptoms :
surgical removal 
which speaciality suits to diagnose and treat :
- general surgery