Consider two neighbors who each run a small business. Juan grows and sells vegetables. Amber grows and sells flowers. Currently, Juan uses a herbicide on his vegetables, because he can grow more crops with the use of herbicide. Specifically, he earns $1500 more during the years when he uses herbicide. Amber's flower farm is harmed by Juan's use of herbicide because it drifts to her farm and kills $3000 worth of flowers each year. Which would be an efficient solution to this problem?

1) There is no need for an intervention, as the current situation is efficient.

2) Amber pays Juan $1500 not to use herbicide.

3) Amber sells her flower business.

4) The government bans the use of herbicide.