正解:C
The first step in selecting a risk response after a penetration test reveals several vulnerabilities in a web-facing application is to assess the level of risk associated with the vulnerabilities, as it involves evaluating the likelihood and impact of the vulnerabilities being exploited, and comparing them with the risk tolerance and appetite of the organization. Correcting the vulnerabilities, developing a risk response action plan, and communicating the vulnerabilities are possible steps in selecting a risk response, but they are not the first step, as they require the prior knowledge of the risk level and the optimal risk response. References = CRISC Review Manual, 7th Edition, page 108.