h1 xfer from company A or B, to company C

[sais]

I had an h1 with consulting agency company A in Texas to be able to
start working from Oct1,2004. They couldn't find me a project but
fortunately I accepted an offer from company B in Colorado on
Oct25,2004 and am currently working for them. My h1 transfer is in a
pending status with them and may not get processed until the mid of
January 2005. However, meanwhile, I have an excellent offer from a
company C in Texas and I really want to move back to Texas. I am not
sure how to deal with this situation.
My questions are:
a) Is my company A's approved h1 is still valid and can that be used
to transfer to company C?
b) Should I use my company company B's pending h1 in order to transfer
to company C under their h1.
c) Should I wait until company B's h1 is approved and then use that to
transfer to company C (that could probably lead to losing the offer
though).
d) Can I start working for company C right away?
e) Does my current employer company B need to know about my h1
transfer to company C?
e) Am I doing something wrong here, please point out?
f) THANKSSSSSSSSSSSSSSSSS for your help!