When one musters something, they are likely to:

When one musters something, they are likely to gather or bring it together. The term "muster" is often used in contexts where someone is called upon to assemble forces, emotions, strength, or support. For example, one might muster the courage to face a difficult situation or muster a team for a project. This implies an active process of collecting or consolidating various elements into a cohesive whole, which aligns with the idea of gathering.

The other options suggest actions that do not relate to the intended meaning of "muster." Losing something implies a lack of control or organization, critiquing involves analyzing or evaluating, and dispersing means to scatter or spread apart, which directly opposes the notion of gathering. Therefore, the best fit for the definition of mustering is to gather or bring together.