Name the term that described the
idea that the united states should
stretch from coast to coast.

It´s the Manifest Destiny.

Explanation:

This doctrine drove relentless American expansion westward during the 19th century. It states that conquering the lands west of its borders and reaching the shores of the Pacific Ocean (thus expanding the country from coast to coast) was God´s will, a natural right of the United States.

b). (sounds as the best answer)

straight down to hell mate