Development of a monitoring well should continue until:

The correct choice indicates that the development of a monitoring well should continue until visibly clear water is discharged. This is essential because the primary goal of well development is to improve the quality of water that enters the monitoring well by removing sediment, debris, and any potential contaminants that may have been present during the drilling process.

When visibly clear water is discharged, it typically shows that the well has been successfully developed, which means that the water is now free of significant turbidity and other particulates. This is crucial for accurate sampling and analysis of groundwater quality, as any particles or contaminants can interfere with the measurements and lead to unreliable data.

In contrast, the other options do not adequately define the primary objective of well development. Stagnant water evaporating does not indicate successful development since evaporation may not relate to water quality. Similarly, removing visible contaminants or ceasing turbulence may not provide assurance of the water's clarity or quality unless it is confirmed that the water is indeed clear upon discharge.