Question: Which street in San Francisco has the most burger restaurants?
SQL: SELECT T2.street_name FROM generalinfo AS T1 INNER JOIN location AS T2 ON T1.id_restaurant = T2.id_restaurant WHERE T1.city = 'san francisco' AND T1.food_type = 'burgers' GROUP BY T2.street_name ORDER BY COUNT(T2.id_restaurant) DESC LIMIT 1