Wrong answer for question.

The statement: "Slack Water: Times when the water movement due to tidal effects are minimal. Note that because of the time it takes for bays and estuaries to drain out, slack water is not necessarily at high tide and low tide. Consult current tables to learn slack water times." The above threw me off the answer of a question on quiz. Meaning that Slack Water does usually occur during high tide and low tide, just not at all places. I mention this for those, like me, that would misunderstand such a statement.