Final answer:
The Scrum Master should reply that all three roles are responsible for the small number of completed items in the first Sprint.
Step-by-step explanation:
The Scrum Master should reply that all three roles are responsible for the small number of completed items in the first Sprint. In Scrum, the three roles are the Product Owner, the Scrum Master, and the Development Team. The Product Owner has the primary responsibility of prioritizing and managing the Product Backlog. The Scrum Master is responsible for facilitating the Scrum process and removing any obstacles that may hinder the Development Team. The Development Team is responsible for delivering the items in the Sprint Backlog.
In this case, it is possible that two of the Development Team members being sick for a number of days during the Sprint may have contributed to the small number of completed items. However, the responsibility for the Sprint's outcome lies with all three roles, as they work together as a team to deliver the set goals.