Which of the following statements are NOT correct?

A. Hydrogen is used to reduce heavy metal oxides to metals.
B. Heavy water is used to study reaction mechanism.
C. Hydrogen is used to make saturated fats from oils.
D. The $\mathrm{H}-\mathrm{H}$ bond dissociation enthalpy is lowest as compared to a single bond between two atoms of any element.
E. Hydrogen reduces oxides of metals that are more active than iron.

Choose the most appropriate answer from the options given below:

Hydrogen reduces some metal ions in aqueous solution and oxides of metals (less active than iron) into corresponding metals.

Heavy water is extensively used as a moderator in nuclear reactors and in exchange reactions for the study of reaction mechanisms.

Dihydrogen is used in the manufacture of vanaspati fat by the hydrogenation of polyunsaturated vegetable oils like soyabean, cotton seeds etc.

Dihydrogen is relatively inert at room temperature due to the high H–H bond enthalpy. Thus, the atomic hydrogen is produced at a high temperature in an electric arc or under ultraviolet radiations.