Among the films that the customer RUTH MARTINEZ has rented, what is the title of the one with the highest replacement cost?
highest replacement cost refers to Max(replacement_cost)
SELECT T4.title 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.first_name = 'RUTH' AND T1.last_name = 'MARTINEZ' ORDER BY T4.replacement_cost DESC LIMIT 1