The moon exerts pull on the earth. The pull stretches the earth's watery envelope and creates tidal bulges. Where the water is thinnest is low tide. The answer is letter A. Moon tides or lunar tides are caused by the pull of gravity between the moon and earth. The moon will exert a gravitational pull on earth and the earth also pulls the moon towards itself. The results is that the moon is near the earth and formation of oceans tide. Even though the earth can hold any object within its proximity, the ocean is partly attracted due to its liquid property. At night, the ocean tends to be attracted to the moon by creating a bulge and assigning it as ‘high tide’. This is due to the strong gravitational pull of the moon to the earth.