What is the dirty electric grid rocky mountains (denver) for the vehicle with the clean electric grid california (san francisco) of 160 g/mi (99 g/km)?
CREATE TABLE table_23840623_4 (
    dirty_electric_grid_rocky_mountains__denver_ VARCHAR,
    clean_electric_grid_california__san_francisco_ VARCHAR
)
SELECT dirty_electric_grid_rocky_mountains__denver_ FROM table_23840623_4 WHERE clean_electric_grid_california__san_francisco_ = "160 g/mi (99 g/km)"
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: What is the dirty electric grid rocky mountains (denver) for the vehicle with the clean electric grid california (san francisco) of 160 g/mi (99 g/km)? ### Input: CREATE TABLE table_23840623_4 (
    dirty_electric_grid_rocky_mountains__denver_ VARCHAR,
    clean_electric_grid_california__san_francisco_ VARCHAR
) ### Response: SELECT dirty_electric_grid_rocky_mountains__denver_ FROM table_23840623_4 WHERE clean_electric_grid_california__san_francisco_ = "160 g/mi (99 g/km)"