Dear Mssus54,
While working in B co you have already filled the transfer form, however, since the status of transfer is unknow, you need check the same with the PF officials. Carry along with you the acknowledgement copy of the transfer request.
So if your amount is already transferred in B co PF account, then you can fill the withdrawal form for B co and C co as you have not transferred the B co amount to C co. So you need to fill 2 withdrawal forms.
If your amount of A co is not transferred in B co then fill 3 forms.
Hope this would clear your doubts. Do reply back or call me at 9867670755.