The correct answer is - B. highland.
The areas in the Tierra Nevada are all areas that are at a very high altitude. Because of that, the climate is much colder, drier, and harsher in general. The forests, shrubs, even the taller grasses can not thrive in those type of conditions, so these areas are only covered in short grasses, dwarfed bushes, and very often do not have vegetation on lot of places at all.
That has led to the development of the highland ecosystems in the Tierra Nevada areas, despite being a region in close proximity to the tropical regions.
