It would be D because "delante" means "in front" while "de" means "of".
Yo y yo? i’m not sure what the context is
If your talking about the present tense of the verb "estar" then it would be estamos, becuase your using the nosotros form of the verb.
I hope this helps you!
Answer:
el conjunto de los números racionales es la razón entre dos números enteros
When stating what you or another person was doing
Example: yo estaba hablando (I was speaking)
Example 2: Tú estabas hablando ( you were speaking)
