Answer the questions about the following sets: D = {x | x is a person allergic to dogs}; C = {x | x is a person allergic to cats}; P = {x | x is a person allergic to pollen} How many people are not allergic to any of the three choices? How many people are allergic to all three choices? How many people are allergic to both dogs and cats but not allergic to pollen? How many people are allergic to cats only?