GST ON RENT TO BANK

Me A owns property in Bangalore rented out to nationalised bank for Rs.1 Lacs per month and also registered with GST ACT.
Now bank says you are not crossing the threshold limit since we will not pay Gst.

whether Mr. A can file nil return under GST ACT?

What will be the implication under GST ACT for Mr A for not charging GST

Can any one clarify with relevant section please

Thanks in Advance