CREATE TABLE table_28538368_2 (mountains_classification VARCHAR2, winner VARCHAR2, general_classification VARCHAR2, points_classification VARCHAR2)

When Alberto Contador Kanstantsin Sivtsov was the general classification and Alessandro Petacchi was the points classification at the same time while Mark Cavendish is the winner, who was the mountain classification?
SELECT mountains_classification FROM table_28538368_2 WHERE general_classification = "Alberto Contador Kanstantsin Sivtsov" AND points_classification = "Alessandro Petacchi" AND winner = "Mark Cavendish"
SELECT "mountains_classification" FROM "table_28538368_2" WHERE "Alberto Contador Kanstantsin Sivtsov" = "general_classification" AND "Alessandro Petacchi" = "points_classification" AND "Mark Cavendish" = "winner"