Although it was old and needed a lot of work Carla knew this was the house for her In this sentence what is the antecedent of the pronoun?

The pronouns in the sentence "Although it was old and needed a lot of work, Carla knew this was the house for her." are:

• "her", the antecedent is Carla.
• "this", the antecedent is house
• "it", the antecedent is house