Which of the following burs is appropriate for a crown-prep setup tray?

A flame-shaped bur is suitable for a crown prep setup tray because it is specifically designed for shaping the preparation and refining the margins of a crown preparation. This type of bur helps in creating the desired contour and reducing the tooth structure appropriately for a crown, ensuring a proper fit for the prosthetic device.

Other burs, such as the round bur, are typically used for creating cavities or removing decay rather than shaping and preparing a tooth for a crown. The round end taper bur is generally used for removing tooth structure in a tapered manner but may not be as effective for the specific contouring needs of a crown prep. Pear burs are often utilized for cavity preparations, helping to create an undercut, which may not be as relevant in the context of preparing a tooth specifically for a crown. Therefore, the flame-shaped bur stands out as the most appropriate choice for this particular procedure.