Final answer:
The best title for the map is 'The rate of Weathering, Erosion and Deposition in the United States,' as it encompasses the entire cycle of these geological phenomena influenced by river systems such as the Mississippi River throughout the country.
Step-by-step explanation:
From the information provided, the most appropriate title for the map would appear to be 'The rate of Weathering, Erosion and Deposition in the United States.' This is because the description details how water from precipitation and melted snow contributes to river discharge which, over time, can erode soil particles, dissolve minerals, and contribute to the geological processes such as weathering and erosion. Rivers, including the Mississippi River and its tributaries such as the Ohio River, play an intricate role in shaping the landscape by transporting sediments downstream and depositing them in various locations, thereby influencing the rate of deposition throughout the United States.
While sediment flow and deposited sediment are parts of the overall process, option B encompasses the entire cycle of these geological phenomena. The title suggested in option B accurately reflects the ongoing processes and changes occurring as a result of environmental factors across the entire country. Considering the drainage basin of the Mississippi River covers about 40% of the U.S., the impact on erosion and deposition is significant, but option D is too specific to just the Ohio River system, and other options do not capture the full scope of the described processes.