A. a. By 2050 almost half a million people in the U.S. alone will be 120 years old or older

B. b. By 2050 almost a million people in the U.S. alone will be over 100 years old

C. c. By 2050 almost half a million people in the U.S. alone will be over 100 years old

D. d. By 2050 almost half a million people in the world will be over 100 years old