If you’re trying to fill in the question the correct answer would be “te portabas”
Answer:
The difference is in what conjugate form you used it in.
Yo : prefiero
Tu : prefieres
El/ella/ud. : prefiere
Nosotros : preferimos
Vosotros : preferis
Ellos/ellas/uds. : prefieren
Explanation:
hope this helps :^)