Question

Which of the following conditions occurs before the tsunami hits the mainland?

Water retreats from the shore

Whirlpools appear in the shallows near the shore

Boats in the open ocean can feel the wave going up and down

A roaring sound can be heard for miles

Answer 1

Water retreats from the shore.

explanation:
the water is essentially doing what you would do if you were to squat before trying to jump very high.

Answer 2

Water retreats from the shore. Water does this to prepare to flood back when the massive waves start coming in.