All of the options listed are characteristics of respectful phone communication. Therefore, the correct selections are:
A. Return phone calls promptly.
B. Introduce yourself immediately in voicemail or phone call.
C. State your purpose and be specific.
D. Provide your contact information clearly in a voicemail.
E. Keep your voice calm and do not interrupt others.
Each of these practices contributes to effective and respectful communication over the phone.