D
The average normal infant born in the United States weighs between 12 and 14 pounds at the age of three months. Ttherefore, if a three-month-old child weighs only 10 pounds, its weight gain has been below the United States average. Which of the following indicates a flaw in the reasoning above?
A: Some three-month-old children weigh as much as 17 pounds.
B: The phrase "below average" does not necessarily mean insufficient.
C: It is possible for a normal child to weigh 10 pounds at birth.
D: Average weight gain is not the same as average weight.