To accurately answer your question about what the starred area on the map represents, I would need to see the specific map in question. However, I can provide a brief description of each option:
A. Gadsden Purchase - This was a 1853 agreement in which the U.S. acquired a small region of present-day southern Arizona and New Mexico from Mexico.
B. Mexican Cession - This refers to the land ceded to the United States in 1848 after the Mexican-American War, which included present-day California, Nevada, Utah, Arizona, and parts of Colorado and New Mexico.
C. Texas Annexation - This refers to the process by which the Republic of Texas joined the United States in 1845, becoming a state.
D. Louisiana Purchase - This was a land deal in 1803 in which the United States acquired approximately 827,000 square miles of territory from France, which doubled the size of the nation.
If you can provide details about the starred area or more context from the map, I can help in pinpointing which of these options it likely represents.