3 is still turning through another lane (the lane with car 2) with oncoming traffic so they have to yield by default because 2 has right of way. Car 3 has no stop sign so they don't have to come to a complete stop to make a left hand turn unless there's a car coming the other way (car 2). 3 also has no yield sign so they don't have to yield for car 1. Car 1 has a yield sign (Which should be a stop sign. Maybe a yield sign there just isn't common where I'm from.) so they have to yield to all other traffic.