I believe the correct answer would be a.
Claudius gives Laertes two reasons why he didn't punish Hamlet yet - he says he loves his mother and that the public loves him. So I guess your answers would be Gertrude loves Hamlet and the King does not want to hurt her and the Danes like Hamlet.
These two options are definitely correct, but if you need another one, then maybe also choose The Danes may not believe Claudius too (however, I am unsure about this one because in the text he only states two reasons).
you cant harm something. harm means hit or damaged
