Reason to obtain gst registration for pwd contractor

I'm a PWD contractor , what reason should i select on gst portal for obtaining registration .

The options in dropdown list are :-

1). Inter state supply

2). Liability to pay as recipient of goods or service .

3). Others 

( Please Ignore the increase in threshold limit , as its mandatory to apply for Maximum of tenders which are invited by department even if we dont have a turnover mentioned for gst registration )