Question 1459Navigation General

The correct answer is B) the lower branch of the observer's meridian. The measurement of local time is based on the passage of the Sun over the lower branch of the observer's meridian, which is the part of the observer's meridian that passes below the observer's horizon. This is because local time is determined by the position of the Sun relative to the observer's location, and the lower branch of the observer's meridian is the part of the meridian that the Sun crosses as it moves across the sky. The other options are incorrect because they do not accurately describe the basis for the measurement of local time. The Greenwich meridian and its upper and lower branches are used for the measurement of standard time, not local time.