The statement that is best supported by the example of polyester is:
D. Producing certain synthetic materials could have a greater environmental impact than disposing of them.
This is supported by the information that producing polyester requires many steps, uses potentially harmful chemicals, and consumes a lot of energy, indicating that the production process has significant environmental impacts. Additionally, while polyester is not biodegradable, it is noted to be easily recyclable, suggesting that the impacts of production may outweigh the impacts of disposal.