To match the metals with their maximum prescribed concentration in drinking water (in ppm), we can use the standard guidelines typically set by organizations like the World Health Organization (WHO). Based on common standards: Manganese ( Mn ) is typically limited to around 0.05 ppm. Zinc (Zn) typically has a higher tolerance and is often limited to around 3.0 ppm. Cadmium (Cd) is very toxic, so it is usually limited to around 0.005 ppm. Copper (Cu) is often limited to around 1.0 to 2.0 ppm, but for the sake of choosing from the given options, we will consider it the highest option which is 5.0 ppm here. Now, let's match these with the given options: (A) Mn−−>(I)0.05 (B) Zn⟶ (II) 3.0 (C) Cd⟶ (III) 0.005 (D) Cu⟶ (IV) 5.0 So, the correct matching is Option D: A-I, B-II, C-III, D-IV