Hello Soumadev Bal!

Actually , Coenzymes and metal Ions that are bound very tightly to the enzyme protien are called prosthetic groups ! This is absolute correct statement . This is because coenzymes are of two types - cosubstrates which are loosely bound and prosthetic grup which are tightly bound . A complete catalytic active enzyme with its bound prosthetic group is called holoenzyme . So A is true and B is false.

Hope this will help you!

All the best for your future!.

Thank you!