Hydrogen peroxide is an effective sterilizing agent. Which one of the following product results when it readily loses active oxygen?

Hydrogen peroxide $\left(\mathrm{H}_{2} \mathrm{O}_{2}\right)$ is a water molecule with an extra oxygen atom. It is very unstable and breaks down readily into water and a single oxygen molecule. So in nutshell, when Hydrogen peroxide readily loses active oxygen, Water is formed.