Speciation is most likely to occur in a species with a number of populations when there is a

(a) small population living in a niche with an environment like that of other population.

(b) small population living in an isolated niche.

(c) large population living in an isolated niche.

(d) large population living in a niche with an environment like that of other populations.

(e) populations in a environment which does not allow it to reproduce at all.