Which insignia denotes the rank of O-7 in the Marine Corps?

The insignia that denotes the rank of O-7 in the Marine Corps is one five-point silver star. This symbol is representative of a Brigadier General, which is the first star rank in the Marine Corps. The silver star serves as a clear and recognizable marker of this rank, distinguishing it from others within the officer hierarchy. The use of stars in military insignia generally indicates a general officer status, with each star representing a specific rank. In this case, a single five-point star signifies the most junior rank of General Officer status in the Marines, making it the correct choice for identifying O-7.