What is the explains the shape of the earth ?

So the shape of the Earth is round.

Explanation:

You know how when you look straight ahead out on the beach? The horizon is a line, right? Well, if the Earth were flat, that line would not exist. Instead, you would see a lot more of the ocean. Try it now and see what I mean. There is a limit to how far you can see, that is because if you stand on a sphere, and someone were to behind standing on the side of it, you wouldn't see them because you would be looking ahead, not down.

the correct answer is d