Which of the following individuals is permissible for initiation according to the Master Mason requirements?

The correct choice highlights the fundamental principle that Freemasonry requires members to be individuals who recognize a Supreme Being. A "true and lawful Brother” signifies someone who has already been initiated into the fraternity and is a member of the lodge, which aligns with the regulations surrounding the initiation process.

In the context of the Master Mason requirements, a true and lawful Brother represents a candidate who is not only of the appropriate age and character but also adheres to the essential tenets expected of Masons, such as moral integrity and respect for the fraternity's values.

The other choices present scenarios that do not meet the initiation criteria. For example, a young man under age does not meet the age requirement typically established for initiation. An atheist is incompatible with the fundamental Masonic requirement of belief in a Supreme Being. Lastly, an old man in his dotage may present challenges regarding his mental acuity or capacity to understand the principles of Freemasonry, which can be critical for initiation. Thus, the choice of a true and lawful Brother embodies the core tenets and requirements for becoming a Master Mason.