How many actors played a role in the 2006 film whose rental duration is 7 days, rental rate is 4.99 and is 98 minutes duration?
in 2006 refers to release_year = 2006; 98 min duration refers to length = 98; number of actors refers to count(actor_id)
SELECT COUNT(T1.actor_id) FROM film_actor AS T1 INNER JOIN film AS T2 ON T1.film_id = T2.film_id WHERE T2.release_year = 2006 AND T2.rental_duration = 7 AND T2.rental_duration = 4.99 AND T2.length = 98