Which of the following can reduce decomposition of ${\mathrm{H}}_2{\mathrm{O}}_2$ on exposure to light

${\mathrm{H}}_2{\mathrm{O}}_2$ decomposes on exposure to sunlight or on heating. It also decomposes on standing but at a slow rate. These reactions occur explosively when ${\mathrm{H}}_2{\mathrm{O}}_2$ is in contact with dust. Urea acts as a negative catalyst to this reaction and slow down the decomposition of hydrogen peroxide.