What is the position of the Sun at True sunset?

The correct answer indicates that at true sunset, the position of the Sun is considered to be one semi-diameter above the visible horizon. This concept is important for navigation and understanding solar phenomena.

At true sunset, the Sun appears to dip below the horizon, but due to atmospheric refraction and the spherical shape of the Sun, it is not actually at the horizon line where it seems to be. The semi-diameter of the Sun refers to half of its apparent size, and it is this physical dimension that accounts for its position relative to the horizon line. The atmospheric effects can cause the Sun to seem visibly above the horizon even when it has technically set. Therefore, knowing that at true sunset the Sun is one semi-diameter above the horizon helps navigators in calculating time and position, especially when using solar observations for navigation.

In this context, other options do not accurately reflect the Sun’s position at true sunset. For instance, referring to the Sun being "at the visible horizon's edge" or "two semi-diameters above the horizon" would not take into account the real effects of its apparent size and atmospheric refraction. Likewise, stating that the Sun is "right at the zenith point" misrepresents its position because the zen