Enter lock with caution is indicated by which signal?

• A. Flashing amber and green lock
• B. Flashing amber
• C. Solid green lock
• D. Steady red lock

Answer: (A)

Interpreting canal lock signals relies on color and flash patterns to tell you what to do. Green signals permission to proceed, red means stop, and amber signals caution. When you see both a green light and amber flashing together, that combination specifically tells you to enter the lock with caution. The green shows you may enter, while the flashing amber adds the warning to proceed slowly and be alert for lock operations, water level changes, or other traffic.

So, the correct signal is the one that blends permission to enter with a caution cue: flashing amber and green. Steady green or flashing amber alone don’t convey that explicit caution-and-entry instruction, and steady red means stop or wait.