Final answer:
The correct definite article to replace the possessive adjective 'su' in the sentence 'Su carro de usted' is 'El'.
Step-by-step explanation:
The correct definite article to replace the possessive adjective 'su' in the given sentence 'Su carro de usted' is 'El'. So, the correct sentence would be 'El carro de usted.'
Learn more about Definite articles in Spanish