What type of food is served at the restaurant located at 3140, Alpine Road at San Mateo County?
3140 Alpine Road at San Mateo County refers to street_num = 3140 AND street_name = 'alpine rd' AND County = 'san mateo county'; type of food refers to food_type
SELECT T2.food_type FROM location AS T1 INNER JOIN generalinfo AS T2 ON T1.id_restaurant = T2.id_restaurant INNER JOIN geographic AS T3 ON T2.city = T3.city WHERE T3.County = 'san mateo county' AND T1.street_name = 'alpine rd' AND T1.street_num = 3140