The correct option is (a).
Explanation
Ocean water is dynamic and constantly in motion. These movements are broadly classified into three categories based on the forces involved (such as wind, gravity, and density differences) and the nature of the movement (horizontal or vertical).
Analysis of the Movements:
- 1. Waves (Correct): Waves are oscillatory movements where water particles move in a circular motion, primarily driven by friction from winds. They represent the horizontal transmission of energy across the ocean surface.
- 2. Tides (Correct): Tides are the periodic rise and fall of the sea level, occurring once or twice a day. They are vertical movements generated primarily by the gravitational attraction of the sun and the moon.
- 3. Ocean Currents (Correct): Ocean currents represent the continuous flow of large volumes of water in a definite direction, similar to rivers flowing within the ocean. They are the primary form of horizontal water movement affecting global climate and navigation.
- 4. Tsunamis (Incorrect): While tsunamis involve massive water movement, they are technically classified as seismic sea waves caused by the displacement of the ocean floor (due to earthquakes or volcanic activity). In standard geographical classification, the "three chief movements" are strictly identified as waves, tides, and currents.
Key Takeaway:
The three fundamental movements of ocean waters are Waves, Tides, and Ocean Currents. Tsunamis are a specific type of high-energy wave caused by endogenic forces, not a primary category of general ocean circulation.