Final answer:
Without a specified growth rate for the second doubling period in the question, it's not possible to choose the correct answer. Historically, population growth rates have been decreasing, which would imply a shorter time than 1,649 years for a population to double again.
Step-by-step explanation:
It seems that the question is missing important details that would specify a particular rate of population growth for the second doubling. From historical data, we know the growth rate can vary significantly. For instance, between 1965 and 1980, the world population grew at an annual rate of 2%, suggesting a doubling time of 36 years. During 2005-2015, the growth rate was predicted to slow to 1.1%, implying a doubling time of 65 years. Additionally, human population growth has consistently been accelerating over time, as shown when it took 120 years to grow from 1 billion to 2 billion, but only 30 years to grow from 2 billion to 3 billion, and even less time subsequently for further billions.
Without a specified growth rate for the second doubling period in the question, we cannot determine the correct answer among options a) 1,649 years, b) 3,298 years, c) 2,298 years, or d) 4,947 years. Historically, the doubling time for the human population has been decreasing due to factors such as technological and medical advancements. Thus, assuming the same or an increased growth rate from the first doubling period would likely result in a shorter doubling time than 1,649 years for the second doubling.