Every high school in the city of Euclid sent a team of 9 students to a math contest. Each participant in the contest received a different score. Andrea's score was the median among all students, and hers was the highest score on her team. Andrea's eight teammates placed 79th, 85th, 91st, 97th, 103rd, 109th, 115th, and 139th, respectively. How many schools are in the city?
15
16
17
18
19