This question is incomplete. Are you struggling with how to respond to the question or you need someone to translate it?
Anyway it is basically asking "What clothes does Carlos buy?"
And if you want to respond you would say it in this format, "<span>Compra el traje azul y una corbata roja." <--- this is just an example. </span>
the correct sentence is yo no tengo ninguna alergia.
1. Por is used to ask questions (por es usado para hacer preguntas)
2. Por is used to refer someone (por es usado para referirte a alguien)
3. Por is used to answer a question (por es usado para responder una pregunta!
