Answer: Tsunami.
Explanation :
Tsunami is the result of a sudden vertical offset in the ocean floor and is most often the result of plate movement on the ocean floor.
Tsunami is caused due to the displacement of a large volume of water like in an ocean. It consists of a series of waves. It destroys coastlines and coastal settlements. It is also known as a tidal wave.
So, the correct option is (b) Tsunami.
"Constant velocity" is practically a definition for zero acceleration.
If you cannot get a chair to move across the floor, it is because static friction opposes your push. When you say static or kinetic friction the two object that facing each other are opposing each other. That's why you're having a hard time pushing the chair.
Answer: Answer to the I'm Tall when I'm Young, and I'm Short when I'm Old. What am I? Riddle is a candle
Hope this helps