D, because the answer is in the question : "a statistic is given that says how many boxcars could be filled with the garbage is dumped into earth's water..."
Answer:
Herbert Hoover (1874-1964), America's 31st president, took office in 1929, the year the U.S. economy plummeted into the Great Depression. Although his predecessors' policies undoubtedly contributed to the crisis, which lasted over a decade, Hoover bore much of the blame in the minds of the American people.
Explanation
D.) Samual F.B Morse invented the electric telegraph