Answer:
B. Clark, and D. Lewis.
Step-by-step explanation:
The two people who were given task to explore the Midwest lands for President Jefferson were Meriwether and William Clark. President Jefferson commissioned Lewis to explore the Midwest lands, comprising of Louisiana Purchase; and Captain Lewis chose Lieutenant Clark to accompany him on this expedition.
Lewis and Clark's expedition is also known as Corps of Discovery expedition. Their exploration began on August 31, 1803, and came to an end on September 25, 1806.
Therefore, option B and D are correct.