What Would Be Appropriate Professional Behavior for the Following Scenario

Multiple Choice

What would be appropriate professional behavior for the following scenario? You are trying to make plans with friends during the day and your friend's text you a message?

A) Inform your students and respond to the text message
B) Leave your phone in your office and wait until you have a break
C) Silence the phone and check it discreetly
D) Step out of the room and respond to the message