The correct answer is - c. Mount Cook.
Mount Cook, or Aoraki as it is known among the native Maori population, is the highest peak in New Zealand. It is part of the Southern Alps, on the South Island. Mount Cook is part of a chain of mountain peaks that run through most of New Zealand and create a beautiful mountainous landscape. This peak is actually getting smaller as the years pass by, and it lost 40 meters of height in the period between 1991 and 2014, and this is mainly caused by rock-slides, and of course, by erosion.