Answer and Explanation:
1.
La computadora - definite article (The) + Noun - Singular
Las computadoras - definite article (The) + Noun - Plural
Una computadora - Indefinite article (A - an) + Noun - Singular
Unas computadoras - Indefinite article (A - an) + Noun - Plural
2.
El cuaderno -definite article (The) + Noun - Singular
Los cuadernos - definite article (The) + Noun - Plural
Un cuaderno - Indefinite article (A - an) + Noun - Singular
Unos cuadernos - Indefinite article (A - an) + Noun - Plural
3.
La mujer - definite article (The) + Noun - Singular
Las mujeres - definite article (The) + Noun - Plural
Una mujer - Indefinite article (A - an) + Noun - Singular
Unas mujeres - Indefinite article (A - an) + Noun - Plural
4.
El chico - definite article (The) + Noun - Singular
Los chicos - definite article (The) + Noun - Plural
Un chico - Indefinite article (A - an) + Noun - Singular
Unos chicos - Indefinite article (A - an) + Noun - Plural
5.
La escuela - definite article (The) + Noun - Singular
Las escuelas - definite article (The) + Noun - Plural
Una escuela - Indefinite article (A - an) + Noun - Singular
Unas escuelas - Indefinite article (A - an) + Noun - Plural
6.
La fotografía - definite article (The) + Noun - Singular
Las fotografías - definite article (The) + Noun - Plural
Una fotografía - Indefinite article (A - an) + Noun - Singular
Unas fotografías - Indefinite article (A - an) + Noun - Plural
7.
El autobús - definite article (The) + Noun - Singular
Los autobuses - definite article (The) + Noun - Plural
Un autobús - Indefinite article (A - an) + Noun - Singular
Unos autobuses - Indefinite article (A - an) + Noun - Plural
8.
El diario - definite article (The) + Noun - Singular
Los diarios - definite article (The) + Noun - Plural
Un diario - Indefinite article (A - an) + Noun - Singular
Unos diarios - Indefinite article (A - an) + Noun - Plural
The words marked in bold correspond to the singular options providing the definite, indefinite articles plus the nouns.
The definite article is the word that determines a noun that is already known by the reader (The), on the other hand the indefinite article is the word that refers to the noun in a general way (Un- una-unos-unas).
