Answer:
Speciation was allopatric or peripatric, but would depend on the number of individuals that dispersed from the original populations.
Step-by-step explanation:
The new species can be formed in one of the three ways that are allopatric, peripatric, and parapatric speciation.
The allopatric speciation gives rise to new species due to the geographical barriers present between them and the peripatric speciation occurs when a small population enters into a new habitat.
In the given question, species A is more closely related to species B as to species C. This could be due to the allopatric speciation or peripatric speciation but it would depend on the number of the individuals of the population that dispersed to a different elevation which provided a new niche.
Thus, the selected option is correct.