Question: in Present Perfect & Answer: in ........ ??

6 years ago

Hey,

if someone ask me: "Have you ever been in jail?" 

and I was in Jail for XXX days/years etc. , how do I have to answer when I'm at the moment of speaking not in jail ?

a) Yes, I have been in jail once for XXX days/years.  -> (I think thats wrong because it's an finished action !? )
b) Yes, I was in prison for XXX years, days etc. 

Sometimes it's confusing. 

Thanks for help.