Which of the following concepts refers to a response to a risk event that was not defined in advance and is currently happening?

Option C is the correct choice.

Option C) WORKAROUND RESPONSE

Because, Workarounds are responses to any unidentified risks that occur during the project execution. 

Thank you for the invitation 

I agee the option C

C. Workaround response.  ------------------

The Answer is Contingency response

B , just like the fall of crane two years ago in Makkah , the fall was not defined and a risk , therfore no contngency or mitigation were defined . every body had to deal with it as an incidence