Nosotras [la] servimos.
Sopa is a feminine noun, thus using a feminine direct object pronoun, which is la.
Answer:
tu
Explanation:
tu is the informal form of you in Spanish. usted is the formal form of you.
What the other guy said was right, I just want to add that if you see something “I drove many times” that would be imperfect. Anything in the past that was done more than once is imperfect
Example
“Yo manejaba muchas veces”
“Yo jugaba cada mes”
“Yo manejé una vez”