When writing a query, write the query in a way that it would work over all possible database instances and not just for the given example instance.

Give an expression in the relational algebra to express each of the following queries:

A. For each product, list the highest, lowest, and average order total amount.

B. Modify the database so that the customer with the last name Smith now lives in Atlanta.

C. Give all orders in this database a 10 percent increase in total amount, unless the total amount would be greater than $100,000. In such cases, give only a 5 percent increase.

D. In February 2022, a new customer named "Manny Sammy" made an order. He lives in "Washington DC". Add the new customer and their order to the database.

Consider the following Employer database schema and example instance: Customers Orders OrderDetails Products