Final answer:
The responsibility that is not a Scrum Master's is assigning tasks to team members. A Scrum Master helps to remove impediments, facilitate meetings, and remind the team of the agile process without directly managing the team.
Step-by-step explanation:
The responsibility that is NOT one of the Scrum Master's is b. Assigning tasks to team members. The Scrum Master's role is to facilitate the process, not to manage the team directly. Scrum Masters help to remove impediments that may be slowing down the team's progress, facilitate meetings such as the daily stand-up, and remind the team of the agile process to encourage self-organization and the ability to create high-value products. In contrast, assigning tasks is a responsibility aligned with the role of a traditional project manager and not the Scrum Master, who empowers the team to decide who will work on which tasks during the task planning activities.