What is the timebox for the Sprint Review?

 The timebox for the Sprint Review is four hours for a one-month Sprint. This is because:

The Sprint Review is an event where the Scrum Team and stakeholders inspect the Increment and adapt the Product Backlog if needed. The purpose of the Sprint Review is to elicit feedback and foster collaboration.

The timebox for each Scrum event is proportional to its frequency and duration. A one-month Sprint corresponds to a maximum calendar month.

The timebox for a one-month Sprint Review is four hours. For shorter Sprints, it is usually shorter.

The timebox ensures that there is enough time to inspect what has been done in relation to what could be done next and make any necessary adaptations to optimize value.

Other options, such as two hours for a one-month Sprint, one day, or as long as needed, are not valid answers as they do not reflect the correct timebox for the Sprint Review.