What is one method to argue against an obviousness rejection?

Demonstrating that the invention is the earliest and predates others is a strong method to argue against an obviousness rejection. This approach highlights the novelty of the invention in relation to prior art, which is crucial in patent law. If an invention is shown to be the first of its kind, it implies that there was no existing teaching or suggestion within the prior art that would lead a person of ordinary skill in the relevant field to arrive at the claimed invention without undue experimentation. This can effectively counter an obviousness rejection, as it underscores that the invention offers something new and non-obvious compared to what is already known.

In the context of the choices provided, demonstrating the invention's earliest date is compelling because it directly addresses the issue of obviousness by showing that the idea was not previously established in any form, thus reinforcing the claim's validity. Other arguments, while potentially relevant in specific situations, do not directly counter the core assertion of obviousness as effectively as showcasing the novelty and priority of the invention.