Figure 4-11 Companies Producing Toilet Paper Bleach the Paper

Figure 4-11 Companies producing toilet paper bleach the paper to make it white.The bleach is discharged into rivers and lakes and causes substantial environmental damage.Figure 4-11 illustrates the situation in the toilet paper market.
-Refer to Figure 4-11.An efficient way to get the firm to produce the socially optimal output level is

A) for government to set a quota on the quantity of toilet paper that the toilet paper industry can produce.
B) to impose a tax to make the industry bear the external costs it creates.
C) to grant a subsidy to enable the industry to internalize the external costs of production.
D) to assign property rights to the firms in the industry.