The angle measured from the observer's meridian, clockwise or counterclockwise up to 180°, to the vertical circle of the body is the __________.

Correct Answer: Option C — azimuth angle

As defined in Bowditch and navigational standards, the azimuth angle is measured from the observer's elevated pole (north or south) along the horizon, eastward or westward up to 180 degrees, to the vertical circle passing through the celestial body.