Sat chem.2

A. 0.020 molar KOH
B. 0.020 molar HNO3
C. 0.020 molar C6H12O6
D. 0.020 molar Mg(OH)2
E. 0.020 molar H2SO4

These solutions use water as the solvent

Which solution has the highest concentration of H3O+ ions ?

The correct answer is E. It said you have to calculate normality. How ? I search formula on internet but didnt understand how to use them.

Pls help
Thank you