In chemistry, one way matter is classified is according to whether it's a pure substance or a mixture. Sodium is an example of a pure substance, while salt water is an example of a mixture.
What do you already know about the difference between a pure substance and a mixture?

the correct answer would be d. hope this !

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.