The correct answer is option C, that is, have a wider range of environments.
It has been known that geographic isolation is a general way for the initiation of the process of speciation, like the rise of mountains, rivers changing course, migration of organisms, continental drift, due to this what was once a steady population gets differentiated into two or more kinds of smaller populations.
A mountain range, due to distinctions in temperature and precipitation as a result of different altitudes, can lead to a higher rate of speciation. Due to these differences, a single mountain range can exhibit an enormous array of biodiversity and climate zones.