Answer:
The options are
A. during the game, a person in a gorilla suit walked into and out of the scene; almost everyone failed to notice
B. during the game, a person in a gorilla suit walked into and out of the scene, nearly half failed to notice
C. a person in a gorilla suit was one of the ball passers, almost no one failed to notice
D. a person in a gorilla suit was one of the ball passers, nearly half failed to notice
The answer is - A. during the game, gorilla suit walked in and out, almost everyone failed to notice.
The experiment by Simon and Chabris in 1999 involved participants watching people passing a basketball around in order to keep track of some activity within the game. The distinctive feature of the scene in which a proportion of people failed to notice was during the game, gorilla suit walked in and out, almost everyone failed to notice.