Tidal terminology: choose the correct statements—(a) the regular periodic rise and fall of the sea surface is called tide; (b) the average difference between high tide and low tide at a place is tidal range; (c) the movement of water caused by the tide is a tidal current.

Introduction / Context:
Tidal definitions are fundamental in coastal and port engineering. They affect harbour accessibility, mooring forces, sediment transport, and design levels.

Given Data / Assumptions:

• Tides cause cyclic water-level changes due to astronomical forcing.
• Tidal range quantifies the vertical excursion between mean high and low waters.
• Tidal currents are the horizontal water motions driven by these level changes.

Concept / Approach:
Each term describes a distinct aspect of the tidal system: vertical oscillation (tide), amplitude (range), and horizontal flow (tidal current). Correct usage is vital for design and navigation notices.

Step-by-Step Solution:
Check (a): Definition of tide—correct.Check (b): Definition of tidal range—correct.Check (c): Definition of tidal current—correct.Thus, all are accurate.

Verification / Alternative check:
Standard oceanographic glossaries confirm these definitions.

Why Other Options Are Wrong:

• Choosing fewer than all misrepresents standard terminology.

Common Pitfalls:

• Confusing storm surges (meteorological) with astronomical tides.

Final Answer:
all of the above.