Explanation:

- The phrase "the point at which the earth and the sky appear to meet" describes the line where the earth's surface and the sky seem to converge.

- Option 1: Crust - This refers to the outermost layer of the Earth. It doesn't relate to where the earth and sky meet.

- Option 2: Horizon - This is the correct term for the line where the earth and sky appear to meet. It represents the boundary in our visual perception.

- Option 3: Rainbow - This is a meteorological phenomenon involving light dispersion, not the meeting point of earth and sky.

- Option 4: Ocean - This is a large body of salt water, not related to the meeting of earth and sky.