According to our current understanding of physics, both the speed of light and infinite velocity are unattainable for different reasons:
Speed of light (c): According to Einstein's theory of relativity, the speed of light in a vacuum, denoted by 'c', is an absolute speed limit in the universe. Nothing with mass can travel at or exceed the speed of light. As an object with mass approaches the speed of light, its energy and momentum increase infinitely, making it impossible to reach or surpass c. This concept is described by the relativistic equations and has been extensively tested and confirmed through various experiments and observations.
Infinite velocity: Infinite velocity, as the term suggests, implies an object traveling at an infinitely high speed. The concept of infinite velocity is not supported by our current understanding of physics. It would imply that an object can cover an infinite distance in a finite amount of time, which violates the fundamental principles of causality and the notion of a finite universe.
In summary, the speed of light (c) is an absolute speed limit in the universe, and objects with mass cannot reach or exceed it. On the other hand, infinite velocity is not considered possible within the framework of our current scientific knowledge.