In a simple database, there are six (6) tables. The database keeps track of restaurants, their owners, customers and their favorite foods. In particular, an owner can own several restaurants. In each restaurant different types of foods are served. Different customers of the restaurant like different types of foods. The database schema is as follows:

Provide a relational algebra for the following queries:

a) List name, gender, and age of all customers.

b) List all male customers older than 65 years of age.

c) List the foods served by at least one restaurant and liked by at least one customer.

DATABASE: RESTAURANT (Restaurant_name[pk], City, Phone, Owner_SSN [fk]) FOOD (Food_name[pk], Type, Country) CUST (SSN(pk], Name, Birth_year, Fav_food[fk], Gender) LIKES (SSN [fk], Food[fk]). SERVES (Restaurant[fk], Food[fk]) OWNER (SSN [pk], Name, City, Address, Phone)