I don't know which one of the next sentences are correct. Please, help me to find out. I also will be appreciated if you'll explain which rules we use here. Where I should to put the "is"?
A) I forgot, how hard is it - to be a policeman.
B) I forgot, how is hard it - to be a policeman.
C) I forgot, how hard it - to be a policeman is.
D) I forgot, how hard it is - to be a policeman
I think, A is a correct answer.