What is the ID of actors that acted in the movies most viewed by audience with occupation 5?
The audience and users are the same meaning
SELECT T3.actorid FROM users AS T1 INNER JOIN u2base AS T2 ON T1.userid = T2.userid INNER JOIN movies2actors AS T3 ON T2.movieid = T3.movieid WHERE T1.occupation = 5 GROUP BY T2.movieid ORDER BY COUNT(T1.userid) DESC LIMIT 1