1, 3, 4, and 7 are true the rest are false.
first here's the definition of a Proxy War : A proxy war is an armed conflict between two states which act or on behalf of other parties that are not directly involved in the hostilities. so the US government aided Africa even though they were not directly involved in the war themselves.
Information in the link below:
https://www.history.com/this-day-in-history/germany-resumes-unrestricted-submarine-warfare
