D.
The greater heat content will be observed as heat energy released from the reaction mixture.
The salt disolves into the solution(water), which creates a new mixture.
<span>The state of matter in which particles are closest together is a solid. This is most easily described by thinking of it in terms of the solid being formed into a particular fixed shape, made possible by the fact the particles are packed tightly, whereas say, a liquid, has loosely packed particles and is free to flow and move (even looser in the case of gases and plasmas)</span>