Final answer:
Phosphatase is the enzyme that exemplifies posttranslational modification by removing a phosphate group from proteins, reversing the action of kinases.
Step-by-step explanation:
The enzyme that exemplifies posttranslational chemical modification by removing a phosphate group is a phosphatase. Phosphatases are involved in the process of dephosphorylation, which is the removal of phosphate groups from proteins that were added through the process of phosphorylation by kinases. This action is crucial as it regulates the function of the protein, often turning off a signal transduction pathway. Among the options provided, the correct answer is C) Phosphatase.