The correct answer to this question is The reaction is not spontaneous under standard conditions. A chemical reaction occurs when substances go through a change. This change is chemical and will change the substance into another substance. These reactions are not just occurring during science experiments. They happen every day, all around the world.
One example of a chemical reaction that we all experience is when we eat food. Our body takes the food and breaks it down, converting the food into energy. As this question indicates, the type of reaction that occurs can vary upon the conditions, as well as the change in energy.