Switched from A to B on H-1B receipt notice, can I join company C on receipt notice w

[Jeena.shah]

Hi, I switched from A to B a week ago on H-1B receipt notice. My H-1B with A is valid until March 2019 and i-94 has the same date. Company C had filed my H-1B while I was with A. Now company C wants me to join them on H-1B receipt. Company C is reputed and like my dream job. I really want to work with them. If I have paySlips from B that means I was never out of status. Am I obliged to tell C that I worked with B ? Can I join C without informing them about B? Will I be legally in trouble later if I do so?