Answer:
C) du studierst / sie studiert
Step-by-step explanation:
In German, verbs conjugate depending on the subject pronoun. Here, "du" is the subject pronoun for the informal "you," and "sie" is the subject pronoun for "they" or the formal "you."
The correct conjugation for "du" is "studierst," while the correct conjugation for "sie" is "studiert."
So, if you want to say "You study" to a friend, you would say "Du studierst." And if you want to say "They study" or "You study" in a formal context, you would say "Sie studieren."
Remember, verb conjugation is important in German to match the subject of the sentence!