H1B transfer with muti employers

[doudou120745]

Hi My situation: I am currently under H4, I have an H1B cap(expire on 08/2017) which allows me to do H1B transfer.

Company A has filed H1B transfer for my on 05/2017, the attorney misdirected us by telling me I can enroll by the time USCIS received my petition. Turns out I can not enroll until my case is approved since I am a H4, without the premium process it may take up to 4 months(or more). It is a shock to me and my employer, although they said they will try their best to wait, things can change quickly.

Now I have received an offer from Company B today, they are willing to file an H1B transfer for me and wait. If I accept their offer, they can probably send out my H1B petition around 07/2017

Question:

1)There is almost 2 months' filing time difference between A and B, if A gets approved first and my status is changed from H4 to H1B, what will happen to B's case, will it be withdrawn?

2)I prefer to work for B but I also do not want A to revoke my case since if B gets denied for some reasons I have no backup plan(my H1B cap expire soon). What is the best option for me?

Thank you!!