Final answer:
The question asks for the correct form of the indefinite article to use before the nouns in Spanish.
Step-by-step explanation:
The subject of this question is Spanish. The question is asking for the correct form of the indefinite article 'a' to use before the words 'lápiz' (pencil) and 'cuadernos' (notebooks).
In this case, the correct answer is 'un' because 'lápiz' is a singular masculine noun. So, the correct sentence would be 'Necesito un lápiz y unos cuadernos.'
The option 'unos' is incorrect because it is the plural form of the indefinite article used before masculine nouns. The options 'unas' and 'un' are also incorrect because they are used before feminine nouns.
Learn more about Indefinite articles in Spanish