单项选择题
Life expectancy among adults 45 and 65 years
of age by family income, sex, and race: United States, average annual
1979-89
A sequence of numbers begins 1, 1, 1, 2, 2, 3 and then repeats this pattern forever. What is the sum of the 135th, 136th, and 137th numbers in the sequence
A． 3
B． 4
C． 5
D． 6
E． 7
B． 4
C． 5
D． 6
E． 7