Environmental Cost Management 
a. Discuss the concept of environmental cost management and its significance for sustainable business practices. Identify and explain the different types of environmental costs, including prevention costs, detection costs, internal failure costs, and external failure costs.
b. ABC Manufacturing Company is implementing an environmental management system to reduce its environmental impact and costs. The company invests in pollution control equipment costing $500,000, which is expected to reduce environmental compliance costs by $100,000 per year for the next five years. Additionally, the company incurs training costs of $50,000 to educate employees on environmental practices. Analyze the costs and benefits of the environmental management system, including the payback period and net present value of the investment.