First series contains the number of days in the months in the order so next months are July and August which has 31 and 31 days. Next series contains the number of letters in those months which is 4 and 6.
A: 31, 28, 31, 30, 31, 30, 31, 31
B: 7, 8, 5, 5, 3, 4, 4, 6