The bond dissociation enthalpy of $\mathrm{E}-\mathrm{H} \left(\mathrm{E}=\text{element}\right)$ bonds is given below. Which of the compounds will act as the strongest reducing agent?

Compound	${\mathrm{NH}}_3$	${\mathrm{PH}}_3$	${\mathrm{AsH}}_3$	${\mathrm{SbH}}_3$
${\mathrm{\Delta }}_{\mathrm{diss}}(\mathrm{E}-\mathrm{H}) \mathrm{kJ} {\mathrm{mol}}^{-1}$	$389$	$322$	$297$	$255$