The table shows the weight of a newborn infant for its first year. During which three-month period was the infant's weight gain the greatest?
0 Months: 7 1/4 lb
3 Months: 12 1/2 lb
6 Months: 16 5/8 lb
9 Months: 19 4/5 lb
12 Months: 23 3/20 lb
F 0-3
G 3-6
H 6-9
J 9-12