Which statement is true regarding the daytime signal for a small vessel engaged in diving operations when underwater shapes cannot be displayed?

Answer: C — A rigid replica of the International Code flag \"A\"

The key concept is signaling diving operations during daylight when you can’t display the usual day shapes. In that situation, the vessel should display a rigid replica of the International Code flag Alpha. This is a standardized, easily recognized signal that divers are in the water and work is being conducted, so other vessels know to keep well clear and proceed with caution. The other flags mentioned don’t convey this specific diving-operations status, so they aren’t appropriate for signaling in this scenario.