I first had an interview at company A, then one a day later at company B.

Company B asked me what other companies I was interviewing with. Since I always try to be honest I told the truth...

But then, Company B told me to compare each company and that they will wait until I finish the other interview process so I could decide.

But is it right? Do I have to decide before a real job offer? How do I tell company B that I want to wait for job offers for me to decide?