Select all the relations which are not functions. O {(2, y) | z is the suggested retail price of particular car and y is price paid by a random car buyer for that car} o {(2, y) | 2 is a day of the year and y is a person born on that day} O {(2, y) | a is the date and y is the value of a stock at the close of the stock market that day} O{(2, y) | a is the population of a town and y is the number of law enforcment officers serving that town} O{(2, y) | a is a randomly selected natural number greater than 6 and y is the remainder when that number is divided by 6}