The water bath should be regulated at a temperature of 25 ± 1 °C (77 ± 2 °F).

• A. 20 ± 1 °C
• B. 25 ± 1 °C
• C. 30 ± 1 °C
• D. 15 ± 2 °C

Answer: (B)

Maintaining a water bath at a precise temperature is essential because many test results depend on a stable environment. The specified target is 25 °C with a tolerance of ±1 °C, so the bath should stay between 24 and 26 °C (77 ± 2 °F). Keeping within this narrow range minimizes temperature-related variability in sample preparation and reactions, leading to more consistent, repeatable results. Other settings would place the bath at a different temperature or outside the required range, which could alter how samples behave and skew measurements. Therefore, the correct setting is 25 ± 1 °C.