D. They were all police forces supportive of only one political group.
Each of the 3 groups were paramilitary groups who supported the fascist rise of Mussolini and Hitler.
The Blackshirts were an Italian military group in support of Mussolini who wore black shirts as part of their uniform. After Mussolini took over, the Blackshirts became a national militia. The Brownshirts and the Schutztaffel were paramilitary groups who supported the rise of Hitler. The Brownshirts were a violent group using intimidation to force support of Hitler. The wore brown shirts as part of their uniform imitating the Blackshirts in Italy. The Schutztaffel or more often referred to as the SS, were Hitler's private military force. The SS were formed out of the Blackshirts and were used for special mililtary operations in Nazi Germany.