You learn that two species of fish co-occurring in a lake evolved into different species because of divergent specialization on bottom- or open water - feeding behaviors.This is a remarkable example of what type of speciation?

A) Rapid environmental speciation, because the environment drove the speciation event
B) Sympatric speciation because the two fish lived in sympatry during the process of speciation
C) Speciation dominated by a chance event, where the chromosome number randomly doubled
D) Allopatric speciation, because the two fish were separated by the water.