Develop SQL queries to retrieve the required information from the following tables.

Items (item_id, designation, price)

Items_ordered (customerid, order_date, item_id, quantity, billing_price)

Customers (customerid, firstname, lastname, city, state)

Note: Some customers get a discount, so the billing_price may differ from the standard price.

a. Select the lastname, firstname, and city of all customers who purchased an item for more that $1000. Display the results alphabetically by last name.

b. Select the firstname, city, and state for the customers who ordered a "tent," and who are living in either Arizona, Washington, Oklahoma, Colorado, or Hawaii.

c. Using Join, list the items each customer ordered where the billing_price was lower than the item price (item, billing_price, and price). Sort the results alphabetically by customer name.