1-A                                                                    1-B
         
                              1-C                                                                                2-A
        
                               2-B                                                                               2-C
         
                            3-A                                                                             3-B
         
                             3-C                                                                               3-D
   
                               4-A                                                                           4-B
   
                                4-C                                                                 4-D
    
                                  5-A                                                                               5-B
 
                                5-C