The correct answer is legislative.
The military falls under the jurisdiction of the legislative portion of the government because Congress (which is the legislative branch) has the ability to declare war. Since Congress has the ability to declare war, not having a military would greatly affect their ability to protect the US. This was one of several problems within the Articles of Confederation. The Articles of Confederation was America's first constitution and was eventually replaced after less than a decade by the US Constitution (still in use today).
