Among the customers who have rented the film ACADEMY DINOSAUR, how many of them are active?
"ACADEMY DINOSAUR" is the title of film; customer refers to customer_id; active refers to active = 1
SELECT COUNT(T1.customer_id) FROM customer AS T1 INNER JOIN rental AS T2 ON T1.customer_id = T2.customer_id INNER JOIN inventory AS T3 ON T2.inventory_id = T3.inventory_id INNER JOIN film AS T4 ON T3.film_id = T4.film_id WHERE T1.active = 1 AND T4.title = 'ACADEMY DINOSAUR'