Help im on exam and its time
(1) Not all students have the opportunity to complete high school. (2) The dropout rate represents the number of 16 to 24 year-olds who do not attend high school and do not have a diploma. (3) The dropout rate declined from 14 percent in 1908 to 8 percent in 2009, due in part to the efforts of schools and teachers. (4) This is excellent news for schools, the students, and the entire community.

Which sentence should have a cited source?
a)Sentence 1

b)Sentence 2

c)Sentence 3

d)Sentence 4