The appropriate preterite form of the verb dormirse in the sentence is:
D. Se durmieron
The complete sentence is:
Ana y Teresa se durmieron en el autobús.
Spanish preterite tense
The verb and the sentence in this exercise are conjugated using the preterite tense. You have to use the Spanish preterite tense ("pretérito perfecto simple" in Spanish) to talk about actions completed at some point in the past.
Check more information about the preterite tense here brainly.com/question/254219
