What regulates the conduct of armed hostilities on land?

The correct answer is that the conduct of armed hostilities on land is regulated by the Law of War. This body of law encompasses various treaties, customs, and conventions that dictate the rules of engagement and the treatment of combatants and non-combatants during armed conflict. It is intended to limit the effects of armed conflict for humanitarian reasons and provides protections for those who are not participating in hostilities, such as civilians and prisoners of war.

The Law of War includes principles such as distinction, proportionality, and unnecessary suffering, which are essential for maintaining ethical standards in military operations. By establishing these rules, the Law of War aims to minimize the suffering caused by warfare and to ensure that military actions are conducted within a framework that respects human rights and dignity.

International treaties and the Geneva Conventions are indeed components of the Law of War, but the term "Law of War" encompasses a broader range of legal frameworks that dictate the conduct of warfare and are not limited to specific treaties or conventions. Military protocol may refer to the procedures and rules followed within an armed force but doesn't provide the comprehensive legal foundation that the Law of War does.