Which of the following is NOT considered a valid license?

The Army Permit is not considered a valid license in the context of this question because it does not confer the legal authority to operate a military vehicle or a commercial vehicle outside of training or supervised environments. In order to drive military vehicles, drivers must hold a Military Driver's License, which is specifically designed for operating these types of vehicles and recognizes the skill and training required in a military context.

Conversely, both the Commercial Driver's License and the Private Driver's License are recognized forms of licensing that provide legal permission to operate commercial and personal vehicles, respectively, under civilian laws. The Military Driver's License is a formal recognition within the military that allows personnel to operate military vehicles, demonstrating that the holder has undergone the necessary training and evaluation.

Thus, while the Army Permit is useful for certain internal military purposes, it does not meet the broader criteria to be recognized as a valid driving license that would apply in general driving contexts.