N/S is playing a variation of Polish Club.
E/W is playing Standard 2/1.
1C could be short generally 2+.
1D waiting, showing a minimum.
1NT tends to cap opener at around 16 HCPs.
2D is presumably running from 1NTx.
Abstain 7NT if you strongly prefer to do something different over 1D.
Abstain normally based on unfamiliarity/confusion with how to deal with N/S's methods.
Plus... it's free!