When waves grow so tall that they topple over, they form ocean breakers called tsunamis fetch crests whitecaps

The correct answer is tsunamis.

Explanation:

Ocean breakers are the waves whose amplitudes reaches up-to critical height and transfer large amount of wave energy into turbulent kinetic energy.

Tsunamis are long high sea waves caused by the earth quakes or other geological disturbances.

Where as Fetch is distance over which wind has blown the water on an ocean or lake to generate waves.

Whitecaps : The waves which white at the top.

Ocean crest is the maximum displacement of the water ijn the upward direction in wave.

Whitecaps

Explanation:

Tsunamis are giant waves, sometimes reaching heights of over 100 feet (30.5 meters), caused by earthquakes or volcanic eruptions under the sea.

A fetch is an area of ocean or lake surface over which the wind blows in an essentially constant direction generating waves.

A crest is the point on a wave with the maximum value of upward displacement within a cycle.  

Whitecaps are waves that grow too high for their bases, therefore they collapse quickly and lose their energy forming a whitish foam.

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