I need urgent help to find out how much water I am under.

Here is my situation:

I came to US in Jan 2007 on Company A visa and immediately got my VISA transferred to company B (without working for Company A).
I got the consultancy job through company B and later on joined (transferred H1 to client) the client itself as full time.
My VISA stamping expired in Oct, 2008. Now, I have to go for visa re-stamping and in DS-157, I have to fill up following:

"12. Not Including Current Employer, List Your Last Two Employers (Kindly mention NA if not applicable under the Name field)".

I was working for Company C in India. I didn't work for Company C in US.
I never had any issue in Visa transfer. Visa from Company A is expired in Oct, 2008.

My questions:
- Should I be skipping Company A as a response to above? Even if I do so, they can easily find out that I travelled to US on Company A VISA.
- If I shouldn't be skipping mentioning Company A, what kind of issues could arise? And how should I be handling that?

Thanks!