The best answer would be B. verdad
Answer:
I believe that it is C. his teacher
Explanation:
The translation: "¡Hable más lentamente, por favor!" Translates into: "Speak more slowly, please!"
Talking in this way could more likely be towards his teacher, if his teacher is teaching and he is asking them to speak slower so Pedro can better understand.
The translation to this sentence is "What is the most expensive gift"