Final answer:
The initial drafting of the Geneva Convention in 1864 had 16 major signatories by the end of that year. It is important not to confuse this event with the establishment of the United Nations in 1945, which included delegates from 50 nations. Option a.
Step-by-step explanation:
The first Geneva Convention was signed in 1864 through the initiative of the International Committee of the Red Cross (ICRC). The initial drafting of the Geneva Conventions had representatives from various nations come together to codify international humanitarian law.
The answer to the question of how many nations were represented at the first drafting of the Geneva Convention is not explicitly provided in the reference material.
However, if this question is pertaining to the first convention, it is historically known that 12 European nations and several American states participated in the conference, leading to a total of 16 major signatories by the end of 1864.
If the question refers to the conventions that were revised and expanded in 1949 (sometimes mistaken for their 'first' drafting), then the answer would be different, as those were adopted in the aftermath of World War II with broader international participation.
For the latter case, which seems to be confused with the establishment of the United Nations in 1945 with 50 nations, it's essential to note that this was a separate event and should not be conflated with the Geneva Conventions.
So option a is correct.