If standard reduction potential \(\left(\mathrm{E}^{\circ}\right)\) of \(\left(\mathrm{Mg}_{(\mathrm{aq})}^{+2} \mid \mathrm{Mg}_{(\mathrm{s})}\right)\), \(\left(\mathrm{Ag}^{+}{ }_{(\mathrm{aq})} \mid \mathrm{Ag}_{(\mathrm{s})}\right),\left(\mathrm{Zn}^{+2}{ }_{(\mathrm{aq})} \mid \mathrm{Zn}_{(\mathrm{s})}\right)\) and \(\left(\mathrm{Cu}^{+2}{ }_{(\mathrm{aq})} \mid \mathrm{Cu}_{(\mathrm{s})}\right)\) are -2.37 V , \(+0.79 \mathrm{~V},-0.76 \mathrm{~V}\) and +0.34 V respectively. Which of the following reaction is spontaneous?

1. A \(\mathrm{Zn}_{(\mathrm{s})}+\mathrm{Mg}_{(\mathrm{aq})}^{+2} \longrightarrow \mathrm{Zn}_{(\mathrm{aq})}^{+2}+\mathrm{Mg}_{(\mathrm{s})}\)
2. B \(2 \mathrm{Ag}_{(\mathrm{s})+} \mathrm{Zn}_{(\mathrm{aq})}^{+2} \longrightarrow 2 \mathrm{Ag}_{(\mathrm{aq})}^{+}+\mathrm{Zn}_{(\mathrm{s})}\)
3. C \(\mathrm{Zn}_{(\mathrm{s})}+\mathrm{Cu}_{(\mathrm{aq})}^{+2} \longrightarrow \mathrm{Zn}_{(\mathrm{aq})}^{+2}+\mathrm{Cu}_{(\mathrm{s})}\)
4. D \(\mathrm{Cu}_{(\mathrm{s})}+\mathrm{Mg}_{(\mathrm{aq})}^{+2} \longrightarrow \mathrm{Cu}_{(\mathrm{aq})}^{+2}+\mathrm{Mg}_{(\mathrm{s})}\)