Which is a property of potassium (k)?

It is highly reactive and when it is kept in open it does react with the oxygen present in the surroundings and burns therefore it is kept immersed in kerosene and please thank me and if you need more comment

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.