Question 469Navigation General

The correct answer is C) heights of topographical features in the United States. Mean high water is the reference datum used to measure the heights or elevations of topographical features, such as land and coastal features, within the United States. This is because mean high water represents the average highest tide level, which is a common reference point for measuring the elevations of nearby land. The other answer choices are incorrect because mean high water is not typically used to measure soundings (water depths) in the United States or worldwide, nor is it used specifically for soundings in European waters.