Answer
a. Exothermic reaction
b. Endothermic reaction
c. Endothermic reaction
Work Step by Step
a. As we can see on page 271, this is an exothermic reaction, for the energy level of the products is lower than that of the reactants.
b. A reaction that $requires$ energy is Endothermic.
c. A reaction that $absorbs$ energy is Endothermic.