In which counties can you find the restaurant with the highest number of branches?
restaurant refers to label; the highest number of branches refers to max(count(city))
SELECT T2.county FROM generalinfo AS T1 INNER JOIN geographic AS T2 ON T1.city = T2.city GROUP BY T2.county ORDER BY COUNT(T1.label) DESC LIMIT 1
database name:db_id restaurant
geographic table geographic Cols: city dtype text, country dtype text, region dtype text, 
generalinfo table generalinfo Cols: id restaurant dtype integer, label dtype text, food type dtype text, city dtype text, review dtype real, 
location table location Cols: id restaurant dtype integer, street number dtype integer, street name dtype text, city dtype text, 
