Final answer:
The three principal mountain chains are the Rockies, the Innuitian Mountains, and the Appalachian Mountains, which makes the correct answer 'All of the above'.
Step-by-step explanation:
The principal mountain chains are A) The Rockies, B) The Innuitian Mountains, and C) The Appalachian Mountains. Therefore, the correct answer is D) All of the above.
The Rocky Mountains are a significant chain in North America, stretching from New Mexico to Northern Canada, formed mainly during the Laramide Orogeny. On the other hand, the Appalachian Mountains span most of the Southeastern United States, with a complex formation history involving multiple collisions, including with the supercontinent Gondwana, during the Pangaea assembly. The Innuitian Mountains, while not as extensively mentioned in the provided information, are another principal chain located in the Arctic regions of Canada, mostly composed of sedimentary rocks.