What is the meaning of two short flashes as a light signal?

The correct interpretation of two short flashes as a light signal is that it indicates "I am operating astern propulsion." This signal is used to inform other vessels that the vessel is predominantly moving in reverse, which is critical information for ensuring safety in navigational contexts. When a vessel is operating astern, it may not be able to maneuver in the same way as when it’s under normal forward propulsion, thereby alerting nearby ships to be cautious.

The other options pertain to different circumstances and light signals. "I am at anchor" would typically be indicated by having a specific anchor light or a symbol designated for that situation. "I am restricted in my ability to maneuver" would usually be communicated with specific shapes or sound signals that indicate the vessel’s condition and its limitations. The statement "I am overtaking" is generally indicated through different communication methods, such as sound signals when approaching to pass another vessel. Thus, two short flashes distinctly signify operating astern propulsion, making it vital for other vessels to understand this maneuver for safe navigation.