Explanation:
Lee's Surrender at Appomattox. Robert E. Lee surrendered to Ulysses S. Grant at Appomattox on April 9, 1865, ending the fighting of the eastern theater and effectively ending the American Civil War.
Aryanazation, The Nuremberg Laws of 1935, Kristallnacht
I believe that the answer is b, because he is a German engineer and the process was named the Siemens-martin process