There are basically three categories of water level fluctuations on the Great Lakes. What is NOT included as one of these?

Correct Answer: Option C — Controlled outflow fluctuations

Great Lakes water levels fluctuate due to short-period, seasonal, and long-range cycles. These are driven by meteorological events, annual precipitation patterns, and multi-year climate trends. Controlled outflow is a management strategy implemented by regulatory boards, not a natural category of water level fluctuation itself.