Answer:
talking
Step-by-step explanation:
This is the girl I was talking about...
Remember that adjectives are words that are meant to modify or describe nouns. In this case, this girl is the noun and talking is the adjective since it is meant to describe the girl in the sentence. More common examples of adjectives would be; They live in a beautiful house, she wears a beautiful dress, and Grace is an adorable baby.
I hope this helps.