What type of price discrimination is described in each of the examples below? Please explain your answer. (a) The metro fares in Singapore vary during the day: a trip at peak hours costs $8, while a trip at off-peak hours costs $3.50. (b) The Economist magazine costs $160 for a one-year subscription, $290 for a two-year subscription and $360 for a three-year subscription. (c) The Movie Theater charges a price of $18 to watch a movie. For children and seniors, the price is instead $6. (d) Mercedes Benz offers a \"Buy One, Get the Second Free\" deal for pink SUVs