Tides are primarily caused by gravitational pulls on oceanic water by the sun and the moon. This is the correct answer (option 3).

Option 1, stating that strong ocean currents dashing against the coasts cause tides, is incorrect. While strong ocean currents can have an impact on water movement near the coasts, they do not directly cause tides.

Option 2, suggesting that strong winds on the surface of the ocean are responsible for tides, is also incorrect. While winds can create waves and affect water movement, they do not directly cause tides.

Option 4, stating that the development of high pressure areas in certain parts of the oceans causes tides, is also incorrect. High pressure areas may affect weather patterns, but they do not directly cause tides.

In summary, the correct answer is option 3, gravitational pulls on oceanic water by the sun and the moon. These gravitational forces cause the water bodies on Earth to bulge, creating the phenomenon of tides.