on the graph above, when x = 1/2, y = 2; and x =1,y=1. The graph is symmetric with repsect to the vertical linke at x = 2. According to the graph, when x = 3, y = ?

a -1
b -1/2
c 0
d 1/2
e 1

its from og11 , q#7.
i dont have og explanation and i am curious how it explains, bec. it took long from me to solve this problem.
pls be kind to post explanation...or give me a link to download og11 Quant explanation

thank u in advance...