3. You should pull over to use the phone
While driving, if you need to use your cell phone, you should pull over to use the phone.
It is advisable to not to use cell phone while driving. Try to put your phone on 'Do Not Disturb' mode or simply don't try to use it while you're driving.
But some times in an emergency, if you need to use your cell phone, then just pull over to use the phone.
You can wait for any safer place to park your vehicle to receive calls if its utmost urgent.