TOPIC: Risk Management

This is a question from RITA book . I have a confusion in this . Can you please clear ??

A System development project is near project closing when a previously unidentified risk is discovered . This could potentially affect the project’s overall ability to deliver . What should be done NEXT ??

A. Alert the Project Sponsor of potential impacts to cost, scope or schedule
B. Qualify the Risk
C. Mitigate the Risk by developing a Risk Response Plan
D. Develop a Workaround

I thought the Answer is D since this is an unidentified Risk , but the answer is B .
Is there a need to Qualify the unidentified Risks before developing a Workaround ??

as a general rule, whenever a risk is identified you have to qualify the risk(assess the priority of the risk), then quantify the risk (numeric analysis of the impact) and only after that you need to work on a risk response plan (options to enhance opportunities and reduce threats).

In real life, all steps can take place in the same time.