H1B change of status, Oct 1st how to make a choice

I am on F1 visa, got H1B approved to work for Employer A from Oct. 1st. But I found Employer B, they just filed a new H1B application for me last Friday. If by Oct.1st, H1B for Employer B is pending, what will be my choice?

(1) Start working for Employer A from Oct. 1st? ( I really want to avoid this, because it is very weird)

(2) Start working for Employer B?

(3) Stay at School by changing H1B to F1?

Thank you