Which One of These Is an Example of Overgeneralization

Which one of these is an example of overgeneralization?

A) Russ takes his teddy bear out for a walk because he has heard that pets need exercise.
B) Uri times himself when he swims laps because he wants to improve his speed.
C) Yolanda thinks she should not go to medical school because she wants to have children and, "You can't be a mom and a doctor, too."
D) Eva wants to take four science classes her first semester in college because she intends to major in science.