Answer:
A.its both actually Andean type mountain buildint event and a collisional event.
over the transcuration of the years ocean ridges and subductions have formed and maintains its constant thickness due to the melting/cooling/and insulation
Explanation:
B. many sciencetists assumed that land is been push upward to form mountains but in reality is earth channels getting steeper and steeper and erosion rate keeps increasing being able for mountains to maintain its high for million of years