Given the task definition and input, reply with output. In this task, you're given a question, a context passage, and four options which are terms from the passage. After reading a passage, you will get a brief understanding of the terms. Your job is to determine by searching and reading further information of which term you can answer the question. Indicate your choice as 'a', 'b', 'c', or 'd'. If you think more than one option is plausible, choose the more probable option to help you answer the question.

Question: What was the price of the land that the United States bought from France in 1803? Passage:Although born a native of Powhatan County, Virginia, William Ashley had already moved to Ste. Genevieve, in what was then a part of the Louisiana Territory, when it was purchased by the United States from France in 1803. On a portion of this land, later known as Missouri, Ashley made his home for most of his adult life. Ashley moved to St. Louis, around 1808, and became a Brigadier General in the Missouri Militia, during the War of 1812. Before the war, he did some real estate speculation and earned a small fortune manufacturing gunpowder from a lode of saltpeter mined in a cave, near the headwaters of the Current River in Missouri. When Missouri was admitted to the Union, William Henry Ashley was elected its first Lieutenant Governor, serving, from 18201824, under Governor Alexander McNair. Ashley ran for governor of Missouri, in the August 1824 election, but was defeated.
Links: a. Gunpowder b. Powhatan County, Virginia c. Missouri Militia d. Louisiana Purchase
d