Can I apply for opt extension(With different employer A ) while h1 (with employer B) under process.and Last date to apply ?

[Raavan]

My 12 month(First opt ) ending on may 31st, I submitted signed i983 to university with Company let say " A" ,but my H1 petition got picked with another company let say " B ".I want to apply for opt extension 
a.what date might be my last date to apply for opt extension (STEM ). 
b.will my OPT extension application(with Company A) affect because of H1b application(with company B). 
c.Can I work for employer "B" while my opt extension under process with employer A I983. 

Please advice me on this.Appreciate your guidance on this..

[shekar11#]

22 hours ago, Raavan said:

My 12 month(First opt ) ending on may 31st, I submitted signed i983 to university with Company let say " A" ,but my H1 petition got picked with another company let say " B ".I want to apply for opt extension 
a.what date might be my last date to apply for opt extension (STEM ). 
b.will my OPT extension application(with Company A) affect because of H1b application(with company B). 
c.Can I work for employer "B" while my opt extension under process with employer A I983. 

Please advice me on this.Appreciate your guidance on this..

a. Your application needs to reach USCIS before May 31st.

b. No.

c. No. You need to submit a new I-983 before joining company B.