Chapter 4, Problem 6RA

Which of these represents an endergonic reaction?

$\begin{array}{l}\text{a}{\text{. ADP+P}}_{\text{i}}\to \text{ATP}\\ \text{b}\text{. ATP}\to {\text{ADP+P}}_{\text{i}}\\ \text{c}\text{. glucose}+{\text{O}}_{\text{2}}\to {\text{CO}}_{\text{2}}+{\text{H}}_{\text{2}}\text{O}\\ \text{d}{\text{. CO}}_{\text{2}}+{\text{H}}_{\text{2}}\text{O}\to \text{glucose}\\ \text{e}\text{. both }a\text{ and }d\\ \text{f}\text{. both }b\text{ and }c\end{array}$