insert pic  Seven children are standing in a circle. No two boys are standing next to each other. No three girls are standing next to each other. Which of these is true for the number of girls standing in the circle? 
选项为:A:only 3 is possible  B:3 and 4 are possible  C:only 4 is possible  D:4 and 5 are possible  E:only 5 is possible  请回答其中一个选项.