attention cell phone users

When you are in a public space (e.g. the library) and your cell phone rings, you have the following four options:
1) Don't answer
2) Turn off the sound and respectfully step outside to answer
3) Answer the phone while pretending to be walking outside so that people who are studying for finals don't give you stink eye
4) If none of the above options suit your fancy, the least you could do would be to turn down the sound on your phone so that the entire library doesn't hear how your father just dropped off a note that he got from your doctor explaining your medical conditions and why you waited until 2 days before the semester ended to try to withdraw from your classes.