Question: In what city is the college preparatory private school where the author of the novel featuring symbologist Robert Langdon and cryptologist Sophie Neveu located?
Sentence (from "Vanguard College Preparatory School"): Vanguard College Preparatory School, founded in 1973, is a private, independent, coeducational, college preparatory day school located in Waco, Texas, United States, for students in grades 7-12.
Relevant evidence: No