Last week, there were several types of animals at a local animal shelter. Let U be the set of the types of animals at the shelter last week. During the week, some of the animals were treated by the veterinarians on staff. Let L be the set of animal types that were treated by Dr. Lu. Let N be the set of animal types that were treated by Dr. Nelson. Let P be the set of animal types that were treated by Dr. Pham. Use the Venn diagram to get your answers below. Consider this set (which is written in descriptive form): The set of animal types that were not treated by Dr. Lu and were not treated by Dr. Pham, but were treated by Dr. Nelson (a) Which of these is a correct way to write the set? (L' ∩ P') ∪ N, (L ∩ P)' ∪ N, (L ∩ P)' ∩ N, (L' ∩ P') ∩ N (b) Write the set in roster form.