A 2023 study tested four water-treatment methods and recorded contaminant removal (% of contaminants) at two pH levels: Method I, 92% (pH 7), 65% (pH 5); II, 88%, 87%; III, 95%, 50%; IV, 86%, 84%. The researchers argued that for variable-pH applications, methods with the highest performance at neutral pH are unreliable; <em>pH stability</em> matters more. The strongest support is ______
Which choice most logically completes the text using the data above?
- A
the average across methods.
- B
Method III's 95% pH 7 performance.
- Ccheck_circle
Method III: highest at pH 7 (95%) but worst at pH 5 (50%); Method IV: lower pH 7 (86%) but stable at pH 5 (84%)—peak pH 7 performance does not predict pH 5 performance.
- D
Method I's pH 7 performance of 92%.
Explanation
The claim is that peak performance misleads—stability matters. Choice B captures the rank reversal between pH 7 and pH 5 (III leads at neutral but lags at low pH; IV is stable). This uniquely supports the nuanced claim.