The diagram represents a taxonomic tree showing the possible evolution of six species of finches.
The most likely explanation for the branching pattern seen in the circled region labeled X is that:
 A. 
environmental changes resulted in extinction
 B. 
speciation occurred as a result of inbreeding
 C. 
no speciation occurred during this time
 D. 
environmental changes influenced speciation
                                             
                                          
                                          
                                       