Identifying Phone Conversation Roles

Below, you see some parts of the phone conversations. (Image shows dialogues by Diana, Jason, Helena, and Mario). According to the speech bubbles above, who is asking the caller to wait for a while? A) Diana B) Jason C) Helena D) Mario

This question includes visual content: The image contains four speech bubbles arranged in a 2x2 grid. On the left are Diana and Helena with purple/orange speech bubbles. On the right are Jason and Mario with grey/yellow speech bubbles. Each person's face is shown next to their respective dialogue. Diana's bubble says 'I beg your pardon. Can you repeat that, please?'. Jason's bubble says 'Please tell him to call me as soon as possible.'. Helena's bubble says 'Could you hold the line, please?'. Mario's bubble says 'I'm calling to get an appointment with Dr. Daisy.'.