Question: When Mark Cavendish wins sprint classification and Maarten Tjallingii wins most courageous, who wins youth classification?
Schema: create table table_25055040_22 (youth_classification varchar, sprint_classification varchar, most_courageous varchar, PRIMARY KEY (youth_classification))
SQL: select youth_classification from table_25055040_22 where sprint_classification = "mark cavendish" and most_courageous = "maarten tjallingii"