Which Mountains classification has a Team classification of quick step?
CREATE TABLE table_5999 (
    "Stage" text,
    "Winner" text,
    "General classification" text,
    "Points classification" text,
    "Mountains classification" text,
    "Combination classification" text,
    "Team classification" text
)
SELECT "Mountains classification" FROM table_5999 WHERE "Team classification" = 'quick step'
Below are sql tables schemas paired with instruction that describes a task. Using valid SQLite, write a response that appropriately completes the request for the provided tables. ### Instruction: Which Mountains classification has a Team classification of quick step? ### Input: CREATE TABLE table_5999 (
    "Stage" text,
    "Winner" text,
    "General classification" text,
    "Points classification" text,
    "Mountains classification" text,
    "Combination classification" text,
    "Team classification" text
) ### Response: SELECT "Mountains classification" FROM table_5999 WHERE "Team classification" = 'quick step'