What gst invoice to issue and return file if tenant register

I am based in Odisha and have rented out commercial property in Odisha to a company registered in Mumbai.  My queries are:

1. What GST shall I charge in invoice, IGST or CGST+SGST?

2. Is the company(registered in Maumbai) eligible to take ITC on GST on rent ?

3. In GSTR 1, shall I put him in B2C (small) or in B2B ?

Thanks in advance