How long is the shortest box available with the Light Duty Crew Cab and the Ram Classic Crew Cab?

The shortest box available with the Light Duty Crew Cab and the Ram Classic Crew Cab is indeed 5' 7". This configuration is popular for those who need a balance between passenger space and cargo capability. In the context of these truck models, the 5' 7" box provides a compact length that makes it easier to maneuver in urban environments while still offering sufficient space for everyday hauling needs.

The other options represent longer box configurations that, while useful for additional cargo capacity, do not apply to the shortest box specifically available for these particular cab types. For example, a 6' 0", 6' 4", or 7' 0" box would provide increased cargo space but would not answer the question about the shortest available size. Therefore, the given dimensions establish the 5' 7" box as the correct answer for the shortest configuration in the specified models.