If she doesn't have enough money, she can't buy that bike.
If I knew your adress, I would have written to you.
<em>Last </em><em>one </em><em>not </em><em>sure.</em>
The <span>sentence in which a pronoun is correctly used as a direct object is:
</span>
C) Nan invited my sister and I to her party.
Direct object refers to the receiver of the action in a sentence; in this case, the direct objects are "my sister" and the pronoun "I" who are the recipients of the party invitation.