Answer:
Ella prefiere que su hijo VAYA (ir) con sus amigos a la exposición.
Step-by-step explanation:
This sentence is in the subjunctive mood because it expresses a preference: “Ella prefiere que” can be translated into “She prefers that” or “She wishes that.” In Spanish, the subjunctive is a mood used to express preferences, wishes, emotions, doubts, guesses, and possibilities.
Since the sentence is in the present subjunctive mood, one must fill in the blank with a subjunctive verb conjugated in the present for the noun “su hijo” (“his son”).
The verb “ir” is an irregular one, so it is conjugated the following way:
Tú vayas
Yo vaya
Nosotros vayamos
Ellos vayan
Él/Ella/eso vaya
The correct word to fill in the blank is: VAYA