There are two sets of figures, the problem figures and answer figures study the problem figure,which make a series and determine the relationship that exist among the problem figure.Keeping this relationship in your mind, choose one figure from the answer figure (A,B,C & D) which may suitably continue the series formed in the problem figures.

http://img87.imageshack.us/img87/2534/problemn.th.png

please explain how to solve this.