Which micronutrient is required is for splitting of water molecule during photosynthesis?

Manganese is a micronutrient required for splitting the water molecule during photosynthesis. In photosystem II of the
thylakoid membrane, the energy from absorbed light is used to split water molecules into oxygen, hydrogen ions
(protons) and electrons. This process is called photolysis of water and requires the presence of a manganese-containing enzyme complex known as the oxygenevolving complex (OEC). The OEC plays a crucial role in the photolysis of water by catalysing the oxidation of water molecules to produce oxygen and protons.
(1) Copper is associated with certain enzymes involved in redox reactions and is reversibly oxidised from Cu+ to Cu2+.
(3) Molybdenum is a component of several enzymes, including nitrogenase and nitrate reductase, both of which
participate in nitrogen metabolism. 
(4) Magnesium activates the enzymes of respiration and photosynthesis, and it is involved in the synthesis of DNA and RNA.