Explanation:

- The sentence discusses the likelihood of war being beneficial. It indicates a contrast or condition related to the benefits of war.

- Option 1: "whether"

- This introduces a conditional or alternative scenario regarding the potential benefits of war.

- Correct: It fits the context as it sets up the discussion about war being beneficial or not.

- Option 2: "therefore"

- This would indicate a conclusive or logical sequence, which doesn’t fit the context of introducing a topic.

- Option 3: "however"

- This is used to present a contrast or exception, but it doesn’t suit the initial description of exploring a scenario.

- Option 4: "since"

- This implies causation or reason, which is not suitable when introducing the topic about a hypothetical situation.