Read the passage and answer the questions that follows. (12) When it comes to applying for admission to a prestigious university, the stakes are high and the competition is fierce. (13) Good grades are a must. (14) Additional credits earned in advanced classes are a significant bonus and usually are expected. (15) Often, however, this is not enough. (16) Students who excel in a sport, who demonstrate artistic abilities, or who actively involve themselves in community activities have an added and distinct advantage over others. (17) To ensure success, the ideal college applicant will meet many requirements: good grades, advanced-placement credits, and an enviable record of extracurricular achievements. (18) Not surprisingly, many students go to bed at night haunted by the following question: "Have I done enough?"
(19) Increasingly, parents are saying that: "Enough is enough!" (20) Many believe that the time has come to put a stop to the ever-escalating demands placed on students today. (21) A variety of solutions has been suggested. (22) They address various aspects of the problem. (23) School officials recommend closer monitoring of classrooms. (24) They suggest tighter controls on Internet use and the installation of security cameras in teachers' offices. (25) These measures might help reduce cheating.
Which sentence uses a colon correctly to introduce examples that support a statement?

19
16
17
18