You Enter a Room and See an Average-Looking Child Wildly

Multiple Choice

You enter a room and see an average-looking child wildly flapping his arms repetitively for no apparent reason. You then notice that this child becomes extremely agitated when an adult pulls a shade on a window down just a few inches. As a knowledgeable psychology student, you would rightly surmise that this child

A) has Down syndrome.
B) is autistic.
C) has muscular dystrophy.
D) is suffering from rubella.