请解释A和B为什么不对

问题如下：

Which of the following situations best illustrates the term “negative externality”?

选项：

A.

The stress that workers take home with them

B.

An unexpected cost increase in an input of production

C.

A product’s price not reflecting the true costs of that product for society as a whole

解释：

C is correct. Negative externalities arise when the private price equilibrium for goods or services does not reflect their true cost. In these situations, the externalized costs are borne by those not involved in the production or consumption of the goods or services or by society as a whole.