A river flows through land used for cotton growing. The cotton farmers applied a large quantity of fertiliser to their fields. This led to eutrophication in the river water. Which option is correct?
- ADecreased levels of mineral salts caused the eutrophication.
- BDesalination of the river water occurred.
- CIncreased levels of phosphates caused the eutrophication.
- DOxygen levels in the river water increased.