Final answer:
The best revision is 'no change' as it maintains a professional and clear tone appropriate for a letter to a mayor. Recycling offers significant environmental and economic benefits and governmental programs can support efforts that enhance these positive impacts.
Step-by-step explanation:
The best revision of the underlined portion of the sentence from Erika's letter arguing that the city should improve its recycling program is: 'no change'. The original sentence 'Imposing stricter recycling regulations would greatly benefit our city in many ways' is already professionally articulated and clearly conveys the positive outcome that stricter recycling regulations could have on the community without sounding casual or informal. The other options either add unnecessary words or take on a less formal tone, which may not be appropriate for a letter to a mayor.
Recycling not only promotes environmental responsibility but also can provide economic benefits that exceed the private benefits. For instance, recycling helps to reduce the amount of waste in landfills and the energy required to process new goods, with certain materials like aluminum and paper being especially effective in regards to energy and resource conservation.
Moreover, government programs that promote activities such as neighborhood clean-up can result in both, improved community aesthetics and reduced expenses for citizens who participate, further demonstrating the beneficial impact of civic environmental initiatives.