The picture shows a bucket being whirled around in a vertical circle, with a help of a string with very high constant speed. What is a correlation between above action and the motion of the moon around the Earth?
All of the above.
The whirling of the bucket with the help of a string is similar to the orbit of the moon around the Earth. Centripetal force makes an object to rotate in a circular motion. The centripetal force in case of the bucket is the tension (The pull of string on the bucket) provided by the string on the bucket. Similarly, the gravitational force between the moon and the Earth act as the centripetal force for its rotation.