A PM has just finished the risk response plan of US$ 387,00 million project. Which of the following should he probably do NEXT?

1) Determine the overall risk rating of the project

2) Begin to analyze the risks that show up in project drawings

3) Add work packages to the project WBS

4) Hold a project reassessment

My answer is 2 but the correct choice is 3. Any explanations? Pls help.