Which pair of words correctly completes this sentence? señor en la foto es abuelo rafael. ese, nuestra este, mi esa, mi aquella, nuestra nextreset

This sentence is in present tense with the 3rd person singular, because señor (gentleman) is él(he).

This sentence is also a good example of the usage of the demonstrative and the possessive adjectives.

The demonstrative adjectives in Spanish are those words that accompany the noun to mark the distance that separates the speaker from the object, place or person to which they refer.

They agree in gender and number with the noun they modify.

The three demonstrative adjectives are:

Este (This): It describes a noun that is close to the speaker and the listener.  

Ese (That): It points out nouns that are further from the speaker and not easily reachable. The noun may be close to the listener, but not the speaker.

Aquel (That over there): It is referred to nouns that are far away from both the speaker and the listener.

Each one has four different forms that vary by gender and number, and they are listed below:

Este

Masculine Singular: Este (This)

Feminine Singular: Esta (This)

Masculine Plural: Estos (These)

Feminine Plural: Estas (These)

Ese  

Masculine Singular: Ese (That)

Feminine Singular: Esa (That)

Masculine Plural: Esos (Those)

Feminine Plural: Esas (Those)

Aquel  

Masculine Singular: Aquel (That over there)

Feminine Singular: Aquella (That over there)

Masculine Plural: Aquellos (Those over there)

Feminine Plural: Aquellas (Those over there)

Note, in Spanish (similar to English) the Demonstrative Adjective is generally written before the noun it modifies.

Now, the possessive adjectives indicate belonging (that someone or something belongs to the noun in the sentence). In spanish, there are two kinds of possesive adjectives:

1. Atonic possessive adjective: they are written before the noun they modify

1st person singular Yo (I): mi/mis (when the noun is plural)

2nd person singular Tú (you): tu/tus (when the noun is plural)  

2nd person singular (formal) Usted (you): su/sus (when the noun is plural)  

3rd person singular Él/Ella/eso/esa (he/she/it): su

1st person plural Nosotros (we):nuestro/nuestra or nuestros/nuestras (when the noun is plural)  

2nd person plural Ustedes (you) (In latinAmerica): su/sus (when the noun is plural)

2nd person plural Vosotros (you) (In Spain): vuestro/vuestra or vuestros/vuestras (when the noun is plural)

3rd person plural Ellos/Ellas (They): su/sus (when the noun is plural)

2. Tonic possessive adjectives: they are written after the noun they modify

1st person singular Yo (I): mío/mía or míos/mías (when the noun is plural)

2nd person singular Tú (you): tuyo/tuya or tuyos/tuyas (when the noun is plural)  

2nd person singular (formal) Usted (you): suyo/suya or suyos/suyas (when the noun is plural)  

3rd person singular Él/Ella/eso/esa (he/she/it): suyo/suya

1st person plural Nosotros (we):nuestro/nuestra or nuestros/nuestras (when the noun is plural)  

2nd person plural Ustedes (you) (In latinAmerica): suyos/suyas

2nd person plural Vosotros (you) (In Spain): vuestro/vuestra or vuestros/vuestras (when the noun is plural)

3rd person plural Ellos/Ellas (They): suyos/suyas

So, in this sentence we have to use the demonstrative adjective Este in masculine singular and the atonic possessive adjective mi.

Therefore the complete sentence is:

This gentleman in the photo is my grandfather Rafael

Note Este (this) is written before the noun señor (gentleman) and mi (my) is written after the same noun.