I had to vote Admiral.

Historically, army officers have been taught and have a natural sense of individuality. A General, of course, would plan attacks, defenses etc. However, how his orders are carried out fall upon every junior officer. If a General were to be captured or killed, especially in this modern day warfare, the other officers are able to effectively take command. If a unit were in retreat, typically, the commanding officer of that unit would be able to organize the retreat and find a proper point without the General's orders.

Now, naval officers, historically, have been taught to follow the orders from the commanding officer in the flagship. A ship does not allow her officers the same tactical flexibility an Army unit does. The only individual options are the issues of fire control and maneuver. It is the Admirals job to plan and direct ships into battle. The fact the admiral is in the midst and must make tactical decisions on the spot causes a fair amount of stress. If a ship were to have an engine malfunction, or if she listed, the Admiral would need to slow down the entire fleet in order to keep that one ship in line. If the flagship were to be destroyed, and the admiral killed, history has shown the fleet is, in effect, a large mob of floating steel with cannon.