下列哪个描述了外部性，哪个没有？解释它们的区别。（1)巴西限制咖啡出口的政策导致美国咖啡的价格

下列哪个描述了外部性，哪个没有？解释它们的区别。

(1)巴西限制咖啡出口的政策导致美国咖啡的价格上升，它反过来又导致茶叶的价格上升。

(2)一则广告传单使一个驾驶汽车的人分心，结果使他撞上一根电线杆。

Which of the following describes an externality and which does not？ Explain the difference.

a A policy of restricted coffee exports in Brazil causes the U. S. price of coffee lo rise, which in tum also causes the price of tea to rise.

b. An advertising blimp distracts a motorist who then hits a telephone pole.