The answer to your question is C.Swing State
The answer is - between Europe, Africa and Asia.
The Byzantine Empire had a territory that was spreading on parts of this three continents, more specifically, it had parts of the edges of this three continents which were trading roots both on land and on sea for centuries before. So the Byzantine Empire took advantage of it and grew enormously in power and wealth because it had control over these trading roots.
Answer:Expand Westward to the Pacific Ocean
Explanation: The whole purpose of Manifest Destiny was to expand west and colonize the rest of the land