Question 4: Consider the following database schema: driver (emp_id, first_name, last_name, salary) route (route_code, from, to, distance, depart_time, arrival_time) bus (bus_id, manufacturer, model, fuel, max_autonomy) has_license (emp_id, bus_id) The driver relation has information about the bus drivers; the route relation indicates each bus route characteristics. The bus relation contains information about each bus. The has_certification relation indicates which drivers have a license to drive a certain bus. For the following queries, provide an expression in (1) relational algebra, (2) TRC, and (3) DRC. - Query a: Find the full names of drivers who have a license to drive buses manufactured by 'Technobus' - Query b: Find the route codes of all the routes that depart from Ottawa after "13:00". - Query c: Find the employee id's of the drivers that have a license to drive electric buses (Hint: Electric buses have fuel = electric)