The letters A,B,C,D and E are to be arranged in the boxes above,one in each box,in the following way.A must be between C and D,B must be next to E,and C cannot be in the first or fifth positions.How many different arrangements of these letters are possible?
A.One
B.Two
C.Four
D.Six
E.Eight
翻译版本是：
ABCDE排列组合,A必须在C和D之间,BE必须相邻,C不能排在第一个和第五个,问共有几种排列?.即4种,为什么呢?
D.