Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_name_77 (engine_type VARCHAR, numbers VARCHAR, length VARCHAR, year VARCHAR)

### Question ###
If length is ft (m) with numbers of 6600-6684 (84 buses) for 2003, what is the engine type?

### Accurate SQL ###

SELECT engine_type FROM table_name_77 WHERE length = "ft (m)" AND year = "2003" AND numbers = "6600-6684 (84 buses)"