Tell me the types of the policy used by the customer named "Dayana Robel".
SELECT DISTINCT t3.policy_type_code FROM customers AS t1 JOIN customers_policies AS t2 ON t1.customer_id  =  t2.customer_id JOIN available_policies AS t3 ON t2.policy_id  =  t3.policy_id WHERE t1.customer_name  =  "Dayana Robel"
types of the policy refers to policy_type_code; used by refers to a JOIN operation between customers, customers_policies, and available_policies tables; the customer named 'Dayana Robel' refers to WHERE t1.customer_name = 'Dayana Robel';