Final answer:
The correct indefinite article for 'mesas' is 'unas', which is used before plural nouns to indicate an undefined quantity.
Explanation:
The correct indefinite article to fill in the blank with 'mesas' is unas.
Indefinite articles like 'unas' are used before plural nouns, indicating an undefined quantity or number of the noun.
For example, 'unas mesas' means 'some tables' where 'unas' is the plural indefinite article.
Learn more about indefinite articles here:
https://brainly.com/question/13246665
