List out the number of object samples in image no.41 which are in the class of "kitchen"?
object samples in the class of "kitchen" refer to OBJ_CLASS_ID where OBJ_CLASS = 'kitchen'; image no.41 refers to IMG_ID = 41 ;
SELECT SUM(CASE WHEN T2.OBJ_CLASS = 'kitchen' THEN 1 ELSE 0 END) FROM IMG_OBJ AS T1 INNER JOIN OBJ_CLASSES AS T2 ON T1.OBJ_CLASS_ID = T2.OBJ_CLASS_ID WHERE T1.IMG_ID = 41