The professional's paramount responsibility is to the public welfare, which includes protecting the environment. However, they also have a duty of fidelity to their client. The correct course of action balances these duties. The professional must fully and honestly inform the client of all findings, including significant environmental risks. Concurrently, they should apply their expertise to propose solutions, such as alternative methods, that mitigate these risks. This approach fulfills the duty to inform the client while upholding the primary ethical obligation to public and environmental safety. It empowers the client to make an informed decision based on a complete picture of both the opportunities and the risks.

A. The professional's role is to advise, not to unilaterally halt a project; this would overstep their authority.

B. Prioritizing the client's economic interests over public and environmental safety is a direct violation of the professional code of ethics.

D. This option incorrectly frames the duty to the client as ensuring economic potential is realized, ignoring the paramount duty to public welfare.

1. APEGS, Code of Ethics (Regulatory Bylaw 20(2)). Guideline 1 states that professionals shall "hold paramount the safety, health, and welfare of the public and the protection of the environment."

2. Andrews, G. C. (2019). Canadian Professional Engineering and Geoscience: Practice and Ethics (6th ed.). Chapter 5, pp. 90-92, discusses the "paramountcy principle," establishing that the duty to the public takes precedence over the duty to the client or employer.

3. Marston, D. L. (2019). Law for Professional Engineers: Canadian and Global Insights (5th ed.). Chapter 22, p. 428, discusses the hierarchy of duties, placing the duty to the public at the highest level.