During Sprint Planning the Product Owner and the Developers are unable to reach an understanding about the highest order

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During Sprint Planning the Product Owner and the Developers are unable to reach an understanding about the highest order Product Backlog items. Because of this, the Developers are unable to determine how many Product Backlog items they can forecast for the upcoming Sprint. However, the Product Owner and the
Developers are able to agree on a Sprint Goal.
Which of the following actions should the Scrum Master support? (Choose two.)

A. Cancel the Sprint. Send the entire team to an advanced Scrum training and then start a new Sprint.
B. Forecast the Product Backlog items that are most likely to meet the Sprint Goal and create the Sprint Backlog. Conclude Sprint Planning and start the development work. Continue to analyze, decompose, and create additional functionality during the Sprint.
C. Continue the Sprint Planning event past its timebox until an adequate number of Product Backlog items are well enough understood for the Developers to make a complete forecast. Then start the Sprint.
D. During the next Sprint Retrospective discuss why this happened and what changes will make it less likely to recur.
E. Ask everyone to take as much time as needed to analyze the Product Backlog first, and then reconvene another Sprint Planning meeting.