which of the following is not an example of price discrimination by a firm?
a. a restaurant charging lower price between 2-4PM than between 12-2PM
b. an electricity firm charging customers higher rate in the winter than  in the summer
c. a senior citizens' discount
d. discount coupons in a newspaper
e. quantity discounts


我觉得都是的么，前四个是第三价格歧视，最后一个是第二价格歧视，我觉得。

做不来，希望哪位大虾帮个忙，看下，最好再解释下，万分感谢