The correct answer is B) the vertical distance from the chart sounding datum to the ocean bottom. Charted depth, also known as the sounding, represents the depth of water as measured from the chart datum to the ocean floor. The chart datum is a tidal reference plane, typically mean lower low water (MLLW), which is used as the baseline for depth measurements on nautical charts. The charted depth does not include the height of the tide, which can vary depending on the time and location. The other answer choices are incorrect because: A) includes the height of the tide, which is not part of the charted depth; C) refers to the average low water level, which is different from the chart datum; and D) describes the average water height over a period, rather than the specific depth measurement.