Answer:
The correct verbal conjugation is:
<u><em>Me gustó.</em></u>
Explanation:
The whole phrase has a past tense expressed, because it has the verb "<em>comer</em>" conjugated as "<u><em>comí</em></u>"
That is why when a person refers to "<u><em>comí</em></u>" you can expect that the next part of the sentence is also in the past form.
It cannot be "<em>me gustaba</em>" because it is the first time the person tastes the food.
It can't be "<em>me gusta</em>", because starting a sentence in the past and then answering it in the present is wrong.