The effect of desalination on the environment among the options provided is:
Brine can kill ocean wildlife.
Desalination processes produce brine, which is a concentrated salt byproduct that is often discharged back into the ocean. This can lead to increased salinity in local waters, potentially harming marine life and disrupting ecosystems.
The other options mentioned (groundwater overdrawn, flooding, and crops contaminated) are not direct effects of the desalination process itself.