The best definition for "belligerent" is the word Hostile. In the Neutrality Act of 1939 there the word belligerent is mentioned, which was used to define hostile nations.
It is a word which defines the hostile characterisitcs of a state or a person. The Neutrality Acts of 1939 mention this term, in this act Congress passed laws to ban the selling of Arsenals to Belligerent Nations during WWll.
Therefore, the correct option is B Hostile.
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