Suppose, you get selected on the base of your skills and fake docs and joined the company and later in verification if they find your certificates are fake then you will be terminated at the same time and company do not even consider your skill sets at that moment.
Fake experience certificates have a nasty way of emerging at times when you least expect them to or you may even have forgotten about them.
Fundamentally, it is incorrect and wrong to build the foundation of your career with sand !!
Given the situation that you are in now, I would suggest you go ahead and submit the 3 years non IT experience and the 1 year IT experience, both of which are genuine. Hope for the best that Company C, doesn't not seek details of your experience from Company B, because if it does, then you will be exposed.
Also, please keep in mind, that there cannot be any guarantee that this will not create a problem in future. There are several instances of very senior people getting caught with resume frauds and having had to resign. Some well known examples are (i) David Edmondson, CEO of Radio Shack, (ii) Marilee Jones, Dean of Admissions at MIT, (iii) Ronald Zarella, CEO of Bausch and Lomb, (iv) Kenneth Lonchar, CFO of Veritas and many many more.
All the best in your career, and please don't embellish it with fiction or fake statements to secure a temporary advantage / benefit.
Does Company C also verify the exp details from Company B?
There is no hard and fast rule that is followed across the board. Requirements for background verification vary from company to company and are also dependent on Company Policy.
Whether Company C verifies details of experience from Company B will depend upon several factors like (i) the nature of the job (for sensitive / complex jobs, many more details are sought that just a confirmation of tenure served), (ii) any small discrepancy that may raise suspicions could trigger a further and deeper check, (iii) the past experience of Company C with respect to background checks that they have conducted vis-a-vis the outcome, and finally (iv) in a small sample of cases, more details are sought - this is like a random sampling.
All the best.