A power-driven vessel is being overtaken in a narrow channel. The vessel agrees to the overtaking. Under Inland Rule 9, which of the following correctly describes the required response of the vessel being overtaken?

1. A. She must sound the danger signal and hold her course and speed.
2. ✓ She shall sound the same signal as the overtaking vessel and may, if specifically agreed to, take steps to permit safe passing.Correct
3. C. She must sound one prolonged blast to indicate she is yielding the channel.
4. D. She is not required to sound any signal; only the overtaking vessel sounds signals.