Which one of the following may be sometimes said as a holder of perpetual neutrality in International…

A neutralised State is one whose permanent neutrality is guaranteed by treaty with other Powers: it undertakes never to go to war except in self-defence, and the guarantor States promise to respect its independence and integrity. Switzerland, neutralised by the Powers in 1815, is the classic example.

An ordinary neutral State is neutral only in a particular war and may give up neutrality later, so it is not a holder of perpetual neutrality. "Impartial State" and "Honest State" are not terms of international law.