If length is ft (m) with numbers of 6600-6684 (84 buses) for 2003, what is the engine type?
CREATE TABLE table_name_77 (
    engine_type VARCHAR,
    numbers VARCHAR,
    length VARCHAR,
    year VARCHAR
)
SELECT engine_type FROM table_name_77 WHERE length = "ft (m)" AND year = "2003" AND numbers = "6600-6684 (84 buses)"
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: If length is ft (m) with numbers of 6600-6684 (84 buses) for 2003, what is the engine type? ### Input: CREATE TABLE table_name_77 (
    engine_type VARCHAR,
    numbers VARCHAR,
    length VARCHAR,
    year VARCHAR
) ### Response: SELECT engine_type FROM table_name_77 WHERE length = "ft (m)" AND year = "2003" AND numbers = "6600-6684 (84 buses)"