Answer:
improving air quality :
1. keep it clean. a clean house may be a healthier house , because good indoor hygiene can greatly cut down on dust and animal dander
2. keep the greenery outdoors
3. change your filters
4. invest in an air purifier
5. let fresh air in
I guess its personal interest really. But if i had to take a wild guess i would say it is D. Why d is because its not really that interesting and stands out because it doesn't give that much detail for what its about. Like why did he retire or what season what is he coaching?