Which amongst the following is/are the duty/duties of Neutral States under International Law ?

Writers such as Oppenheim group the duties of a neutral State under three heads: abstention (it must not help either belligerent with troops, arms or loans), prevention (it must stop belligerents from using its territory or waters for war), and acquiescence (it must tolerate lawful belligerent acts such as visit, search and capture of its merchant ships).

All three are recognised duties of neutrality.