A is correct because the Scrum team is the one that determines the tasks that are required to complete the committed backlog items in a Sprint. The Scrum team is a self-organizing and cross-functional group of people who work together to deliver a potentially releasable increment of the product at the end of each Sprint.
The Scrum team breaks down the user stories into smaller and manageable tasks, and assigns them to the team members based on their skills and availability.