Analyze the map below and answer the question that follows.

A topographic map of mainland Southeast Asia. three lines are labeled A, B, and C. Line A goes through Burma. Line B starts in the Middle of Thailand and ends in Bangkok. Line C goes through Laos, Thailand, and Cambodia to the coastline.
Image courtesy of the CIA World Factbook

The lines marked by the letters A, B, and C on the map above represent .
A.
chains of volcanoes
B.
earthquake fault lines
C.
thin strips of heavy forests
D.
major rivers that flow from north to south