Paragraph 2 discusses two different types of thermochemical reactions. In one type of reaction, the enthalpy term is located on the reactant side of the equation. Which type of
reaction is this?

The reaction is endothermic.

Explanation:

Endothermic reaction : It is a type of chemical reaction where the energy is absorbed from the surrounding. In the endothermic reaction, the reactant have less energy than the energy of products

In endothermic reaction, enthalpy terms is located on the reactant side.

Example:

Exothermic reaction : It is a type of chemical reaction where the energy is released into the surrounding. In the exothermic reaction, the energy of reactants are more than the energy of products

In exothermic reaction, enthalpy terms is located on the product side.

Example:

the answer would be a