Final answer:
The Salon des Indépendants in Paris introduced Cubism to the public on 21 April 1911. Cubism was an influential art movement led by Picasso and Braque, developing new styles of painting multiple perspectives in one artwork.
Step-by-step explanation:
In 1911, the Salon des Indépendants in Paris brought Cubism to the attention of the general public. The event took place on 21 April, which is option a). Cubism was characterized by a new style of painting that captured the essence of subjects in fragmented pieces to form multiple perspectives within a single painting. The movement, which began around 1907, was remarkably influential, with Pablo Picasso and Georges Braque leading the way and revolutionizing the western ideas of how space should be depicted in two dimensions.This event marked a significant moment in the history of Cubism, as it introduced the revolutionary art movement to a wider audience.