Final answer:
In chronic apical periodontitis, a single-rooted tooth would be expected to respond to heat, cold, and electric pulp tester.
Step-by-step explanation:
In the given pathologic conditions, a single-rooted tooth would be expected to respond to heat, cold, and electric pulp tester (vital).
Out of the options provided, the correct answer is C. Chronic apical periodontitis.
In chronic apical periodontitis, the tooth is still vital, meaning the pulp is still alive. Therefore, it will respond to thermal and electric stimuli.