The main cause of the changing location of the tides on earth is

-rotation of the Earth on its' own axis
- magnetic forces of the Moon
- the revolution of the Moon around the Earth ***
-the position of the Sun

I disagree. The tide is high twice a DAY because the earth spins under the moon putting the moon over Gloucester once a day and exactly opposite Gloucester every day. In both cases the water rises either toward the moon when you are under it or away from the moon when you are opposite the moon, further from the earth moon center of gravity and the water spins away due to centripetal acceleration.

If it were due to the motion of moon around earth you would get 2 tides a MONTH (it does have a smaller effect, leading to increased full and new moon tides called spring tides or the weather folks (landlubbers) call the "astronomical tides")

so then it has to be "a" since the earth revolves in its axis in a 24 hour period of time

Yes

Did no teacher do the ping pong ball, tennis ball and soccer ball thing in your class?

so then it has to be "a" since the earth revolves in its axis in a 24 hour period of time

The main cause of the changing location of the tides on Earth is the revolution of the Moon around the Earth. To understand why this is the case, let's break it down.

Tides are the rise and fall of sea levels caused by the gravitational interaction between the Earth, Moon, and Sun. The Moon's gravitational force has a significant influence on the ocean's water, causing it to bulge towards the Moon.

As the Moon revolves around the Earth, this bulge moves along with it, creating high tides on the side of the Earth closest to the Moon and on the side opposite to the Moon. These are known as the high tide bulges.

Now, you might be wondering why the changing location of the tides is specifically due to the Moon's revolution rather than any of the other options provided in the question.

The rotation of the Earth on its own axis does not directly affect the changing location of the tides. It causes the regular pattern of two high tides and two low tides every day, known as the diurnal tide pattern.

The magnetic forces of the Moon refer to its gravitational force, which is indeed a significant factor, but it is the Moon's revolution that causes the changing location of the tides.

The position of the Sun also plays a role in creating tides, especially during spring tides and neap tides. However, while the Sun's position affects the tide height, it does not significantly contribute to the changing location of the tides.

In summary, the revolution of the Moon around the Earth is the primary cause of the changing location of the tides on Earth.