Which of the Following Is an Example of Good Etiquette

Which of the following is an example of good etiquette for cellphone conversations and texting?

A) keep your ringer on at all times so you don't miss a phone call
B) check your email as soon as it comes it regardless of what you are doing so you don't miss something important
C) avoid cellphone conversations in enclosed spaces such as elevators, waiting rooms, busses or trains
D) ensure you use a loud voice so the person on the when can hear you
E) respind to texts immediately even if you are in a face to face conversation with someone else