Which of the Following Descriptions Best Represents the Gradual Model

Which of the following descriptions best represents the gradual model of speciation?

A) Species undergo little change over long periods interrupted only by short periods of rapid change.
B) An isolated population differentiates quickly from its parent stock as it adapts to its local environment.
C) Speciation occurs regularly as a result of the accumulation of many small changes.
D) Speciation occurs under unusual circumstances and therefore transitional fossils are hard to find.