Specified feeding relationships
 Descendant                   Mother
 RULE-D                       RULE-D
 RULE-D                       RULE-B
 RULE-D                       RULE-C
 RULE-A                       RULE-D
 RULE-A                       RULE-B
 RULE-A                       RULE-C
 RULE-B                       RULE-D
 RULE-B                       RULE-B
 RULE-B                       RULE-C
 RULE-C                       RULE-D
 RULE-C                       RULE-B
 RULE-C                       RULE-C