Final answer:
The Corps of Discovery's journey had several purposes, but finding a direct water route to the Pacific Ocean was not one of them. Option C is the correct answer.
Step-by-step explanation:
The Corps of Discovery's journey, led by Meriwether Lewis and William Clark, had several reasons, including exploring the newly acquired Louisiana Territory, establishing trade with Native American tribes, and documenting new plant and animal species. However, the reason that was NOT one of their goals was to find a direct water route to the Pacific Ocean. Despite their failure to find the Northwest Passage, their expedition was still considered a significant achievement.