CREATE TABLE table_73722 ("Stage" FLOAT, "Winner" TEXT, "General Classification" TEXT, "Youth Classification" TEXT, "Mountains Classification" TEXT, "Sprint Classification" TEXT, "Most Courageous" TEXT, "Team Classification" TEXT)

When Mark Cavendish wins sprint classification and Maarten Tjallingii wins most courageous, who wins youth classification?
SELECT "Youth Classification" FROM table_73722 WHERE "Sprint Classification" = 'Mark Cavendish' AND "Most Courageous" = 'Maarten Tjallingii'
SELECT "Youth Classification" FROM "table_73722" WHERE "Most Courageous" = 'Maarten Tjallingii' AND "Sprint Classification" = 'Mark Cavendish'