Which category earlier than 2006 has Bart Brentjens as rider 2?
CREATE TABLE table_71757 (
    "Date" real,
    "Category" text,
    "Team" text,
    "Rider 1" text,
    "Rider 2" text
)
SELECT "Category" FROM table_71757 WHERE "Date" < '2006' AND "Rider 2" = 'bart brentjens'
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 category earlier than 2006 has Bart Brentjens as rider 2? ### Input: CREATE TABLE table_71757 (
    "Date" real,
    "Category" text,
    "Team" text,
    "Rider 1" text,
    "Rider 2" text
) ### Response: SELECT "Category" FROM table_71757 WHERE "Date" < '2006' AND "Rider 2" = 'bart brentjens'