SELECT T1.last_name FROM Owners AS T1 JOIN Dogs AS T2 ON T1.owner_id  =  T2.owner_id WHERE T2.age  =  ( SELECT max(age) FROM Dogs )
Who owns the youngest dog? Give me his or her last name.
SELECT T1.last_name FROM Owners AS T1 JOIN Dogs AS T2 ON T1.owner_id = T2.owner_id WHERE T2.age = ( SELECT max ( age ) FROM Dogs )
select t1 . last_name from owners as t1 join dogs as t2 on t1 . owner_id = t2 . owner_id where t2 . age = ( select max ( age ) from dogs )
Who owns the youngest dog ? Give me his or her last name .