Final answer:
Researchers believe that the first barley-based beers were developed in Mesopotamia, present-day Iraq, where the earliest evidence of grain domestication and agriculture in the Fertile Crescent has been found. Option b is the answer.
Step-by-step explanation:
The first development of barley-based beers is thought to have occurred in the region known as Mesopotamia, which corresponds to modern-day Iraq. This stems from archaeological discoveries that place the earliest evidence of agriculture and the domestication of grains in the Fertile Crescent. Specifically, around 10,000 BCE, wheat and barley were first domesticated in areas that include modern-day northern Iraq. Furthermore, evidence of ancient breweries dates back to approximately 3500 BCE, with Egypt having some of the oldest known breweries in the world, suggesting the practice of beer-making was highly advanced in this area. However, based on the context of beer production as a significant development in the Fertile Crescent, which is within modern Iraq, it is suggested that Iraq is the most likely candidate for the development of the first barley beers.