What is the maximum amount of time a sprint retrospective should take?

The Sprint Retrospective is a formal opportunity for the Scrum Team to inspect itself and create a plan for improvements. According to the official Scrum Guide, this event is timeboxed to a maximum of three hours for a one-month (approximately 30-day) Sprint. For Sprints of a shorter duration, the event is usually shorter. The question asks for the maximum amount of time, which directly corresponds to the guideline for the longest standard Sprint duration.

A. 1 hour is a common duration for a one or two-week Sprint's retrospective, but it is not the maximum time allowed for a month-long Sprint.
B. 1.5 hours is a typical timebox for a two-week Sprint's retrospective, not the maximum for a one-month Sprint as specified by the Scrum framework.

1. Schwaber, K., & Sutherland, J. (2020). The Scrum Guide. Scrum.org. Page 10. ("The Sprint Retrospective is timeboxed to a maximum of three hours for a one-month Sprint.")

2. Stray, V., & Paasivaara, M. (2021). Agile Software Development. University of Oslo, INF5181 Course Material. Lecture 3: Scrum. Slide 33. (Reiterates the timeboxes for Scrum events, including a 3-hour retrospective for a 1-month sprint).