Which country produced the most expensive car in 1970?
the most expensive refers to max(price); in 1970 refers to model_year = 1970
SELECT T3.country FROM data AS T1 INNER JOIN production AS T2 ON T1.ID = T2.ID INNER JOIN country AS T3 ON T3.origin = T2.country INNER JOIN price AS T4 ON T4.ID = T1.ID WHERE T2.model_year = 1970 ORDER BY T4.price DESC LIMIT 1
database name:db_id cars
country table country Cols: origin dtype integer, country dtype text, 
price table price Cols: ID dtype integer, price dtype real, 
data table data Cols: ID dtype integer, mileage per gallon dtype real, number of cylinders dtype integer, displacement dtype real, horse power dtype integer, weight dtype integer, acceleration dtype real, model dtype integer, car name dtype text, 
production table production Cols: ID dtype integer, model year dtype integer, country dtype integer, 
