For every x million US dollars exchanged in a market, a total of B(x) million dollars in economic benefit are generated, where B(x) = x+6- 620.3Vx (a) At what rate is the economic benefit changing with respect to x when 324 million dollars are being exchanged? Rate: (b) Write a sentence to interpret your result in part (a), including units. (c) Over time, the amount of money exchanged in the market shifts, such that x = 1.8 + 324, where t is the number of days from now. At what rate is the economic benefit changing with respect to t now? Rate: million dollars per day Upload all of your work for parts (a) - (c) to the "Practice Final Exam" assignment on Canvas. Type "upload" (with no quotation marks) in the answer blank below to indicate that you will upload your answers. (d)