Thanks. Master 8. The reason about pay stub is that my H1b is still under company C sponsor, not company A. And I don't have document about the spin off from company CSo, I am worrying that this may cause the rejection of H1b transfer.
-You need to provde the paycheck stubs from Compnay A, otherwise your H1 transfer approval will have no I-94 and thus you need to go outside US to get the H1 visa. You may just need to address in the cover letter that the Company A is successor-in-interest of Company C so that you are legal to work for Company A. Talk to the lawyer and he/she should know ho to deal with it.