A researcher has hypothesized that the chemical tributyltin (an additive in boat paint) seeps into the water causing reproductive defects in developing marine snails. In an experiment testing the effects of tributyltin on developing snails, which condition should be used as a control?

A) Developing snails are kept in a tank of water and exposed to below-expected levels of tributyltin.
B) Developing snails are kept in a tank of water and exposed to boat paint without tributyltin.
C) Developing snails are kept in a dry tank to avoid exposure to contaminated water.
D) Developing snails are kept in a tank of water that has been cleaned with chlorine bleach.