My I140 is with employer A. Before completing 6 months with this I140, employer A spun off our division into a separate company (employer B). Now, employer B has restarted my green card process (right now, at PWD stage).

a) Is my I140 still valid? My H1B with employer B was renewed based on that I140. I am in my 7th year of H1B

b) Can I join employer C based on I140 from employer A?