Which question is addressed to "usted" (talking to someone with formal respect)?

Con quien hablaste?
¿De qué hablaste?
¿Cuánto tiempo estuviste en el teléfono?
Que compraste en la tienda?
¿Que hiciste después
¿Te dormiste al colgar el teléfono?
Te despertaste a tiempo para ir a la escuela?
¿Tuvo un sueño anoche?
Que comeriste en la mañana

These are not asked formally but informally. A peer, or a friend, or someone on a first-name basis with you is asking the question. Now, what do you want to do with these questions? Answer them? OR change them to the formal? Your instructions are lacking as to what you are supposed to do with these questions?

Sra

The only one asked formally, or of usted, is: ¿Tuvo un sueño anoche?

The last is definitely an error: ¿Qué comiste?" What DID you eat...

Sra

To identify which question is addressed to "usted" (talking to someone with formal respect), you need to look for the use of the formal second-person pronoun "usted".

The correct question addressed to "usted" is:
¿Tuvo un sueño anoche?