Jawabanmu

2014-09-02T15:45:52+07:00
X={4,5,6,7}
A.{1,2,3,4,5,6,7}
B.{7,8,9,10,...}
C.{4,5,6,7}
D.{3,4,5,6,7}
jadi, jawabannya C.