Answer: A) taste.
Explanation: An action verb is a verb that explains what the subject of the sentence (person, animal or object) is doing or has done. In the given sentence the action verb is "taste" because it indicates an action (something that the subject "I" has done). The other verb in the sentence is "feel," it isn't an action verb because it is just a consequence of tasting something warm (it isn't something that the subject does on purpose).