The correct answer is (a) Bihar.
Bihar recorded the highest decadal growth rate of population during 1991-2001, with a growth rate of 28.59%. This was followed by Nagaland (28.08%), Uttar Pradesh (25.85%), and Sikkim (24.81%).
The high growth rate in Bihar can be attributed to a number of factors, including a high fertility rate, a low mortality rate, and a large number of young people. The high fertility rate is due to a number of factors, including traditional social norms that favor large families, a lack of access to family planning services, and a lack of education and employment opportunities for women. The low mortality rate is due to improvements in healthcare and sanitation. The large number of young people is due to the high fertility rate in previous decades.
The high growth rate in Bihar has a number of implications, including a strain on resources, such as food, water, and energy; an increase in pollution; and a decrease in the quality of life. The government of Bihar is taking a number of measures to address the challenges posed by the high growth rate, including investing in education and healthcare, promoting family planning, and creating employment opportunities.