The standard reduction potentials at `25^(@)C` for the following half reactions are given against each:
`Zn^(2+) (a.q) + 2e^(-) hArr Zn (s) : " " - 0.762`
`Cr^(3+) (a.q) 3e^(-) hArr Cr (s) , " " - 0.740`
`2H^(+) + 2e^(-) hArr H_(2) (g), " " 0.00`
`Fe^(3+) + e^(-) hArr Fe^(2+) , " " 0.77`
Which is the strongest reducing agent?
A. `Zn`
B. `Cr`
C. `H_(2)(g)`
D. `Fe^(2+) (aq)`
