Answer:
Pude.
Step-by-step explanation:
In orde to respond this correctly you have to read the sentence and realize who is talking, the narrator is talking in first person, and in the past, that means that we have to conjugate the verb in first person and in the past tens, the verb poder in past and first person would be "Pude" so that would be the correct answer.
HAce 2 años, yo PUDE solicitar la ciudadania.