Which of the following, if true, most helps to support Quintero's alternative proposal? A. Some rooms at the high school cannot be converted into rooms suitable for the use of elementary school students. B. The cost of building a high school is higher than the cost of building an elementary school. C. Although the birth rate has not increased, the number of families sending their children to the region's high school has increased markedly. D. A high school atmosphere could jeopardize the safety and self-confidence of elementary school students. E. Even before the region's high school population began to decrease, several high school classrooms rarely needed to be used.