t] {B}}              [0,red,edge label={node[midway,right] {C}}]             [0,red,edge label={node[midway,right] {D}}]         ]    [0,red,edge label={node[midway,right] {C}}             [0,red,edge label={node[midway,right] {B}}]             [0,red,edge label={node[midway,right] {D}}]             ]         [0,red,edge label={node[midway,right] {D}}             [0,red,edge label={node[midway,right] {B}}]             [0,red,edge label={node[midway,right] {C}}]             ] 