In ​, the estimated world population was 7.5 billion. Use a doubling time of 37 years to predict the population in ​2062, 2072​, and 2117.

a) 13.5 billion, 15.5 billion, 23 billion
b) 15 billion, 18 billion, 30 billion
c) 22 billion, 28 billion, 56 billion
d) 30 billion, 40 billion, 80 billion