Final answer:
Some of the first security guards in ancient Egyptian royal households came from the ranks of professional soldiers, trained and disciplined for such protective roles.
Step-by-step explanation:
The royal households of ancient Egyptians hired security guards from various backgrounds. Given the options provided, some of the first security guards came from the ranks of professional soldiers. Historical records suggest that these guards often had a military background, which provided them with the training and discipline required to protect important individuals and property. For example, in the Ottoman Empire, the Janissaries served a similar function as an elite infantry corps and household guard to the sultan, chosen for their loyalty and military skill.
Furthermore, in ancient societies, professional soldiers frequently took on the role of protectors and enforcers. This is reinforced by looking at other ancient cultures, such as the samurai in Japan, who served as elite warriors and protectors for their masters.