Which one of the following statements is not true?

• A. Gulfs with narrow fronts and wider rears experience high tides
• B. Tidal currents take place when a gulf is connected with the open sea by a narrow channel
• C. Tidal bore occurs when a tide enters the narrow and shallow estuary of a river
• D. The tidal nature of the mouth of the river Hooghly is of crucial importance to Kolkata as port