According to the Scrum Guide, the Developers are accountable for creating a plan for the Sprint, which includes selecting the Product Backlog items that they can deliver in the Sprint1. If they realize that the workload is too high, they have two options: either reduce the scope or increase the capacity. Reducing the scope means removing or changing some of the Product Backlog items, in agreement with the Product Owner, so that the Sprint Goal can still be achieved2. Increasing the capacity means adding more Developers to the team, but this is not recommended, as it can disrupt the team dynamics, lower the quality, and increase the communication overhead3. Therefore, the best actions to take are A and B, as they respect the self-organization and collaboration of the Scrum Team, and allow them to deliver a valuable and potentially releasable Increment at the end of the Sprint4.