Phosphate Ions, PO₄^3-, Were Once Added to Detergents to Assist

Phosphate ions, PO₄^3-, were once added to detergents to assist in cleaning. What function did they serve?

A) Phosphate ions were relatively good at removing grease by binding with large nonpolar molecules.
B) Phosphate ions were large enough to bind with the large grime molecules and remove them.
C) Phosphate ions would bind to and remove calcium ions, thus acting as a water softening agent.
D) Phosphate ions would reduce the growth of algae in aquatic habitats receiving the waste water.