Consider the following relations: salesperson(emp#, name, age, salary); key is emp# order(order#, cust#, emp#, amount); key is order# customer(cust#, name, city, industry-type); key is cust# Show SQL expressions for the following queries: a. all the information of customers who have placed more than one order with Salesperson "Smith". b. the name and the age of the oldest salesperson whose salary is below the average salary. c. the name and the total number of order for each salesperson whose customers are from the NEW YORK City. d. the names and salary of salespersons having orders of chemical type and city is not from LA.