In what way did the purpose of Alaska fit with the security of state, William Seward foreign policy toward Asia?

A Seward thought the purpose of Alaska could protect the United States from Asian aggression
B Siri thought that Alaska could be a steppingstone to increase trade with Asia
C Seward thought that the purpose of Alaska would we can, Japan and other agent powers
D Seward thought the purpose of Alaska would make it possible to annex Midway Island

A. Seward thought the purpose of Alaska could protect the United States from Asian aggression.