The Graphs Below Refer to the Market for Good X

The graphs below refer to the market for good X.Firms can produce either good X or good Y,which consumers consider to be a substitute for good X.A decrease in the price of good Y will to lead to the shifts shown by

A) Graph (a) .
B) Graph (b) .
C) Graph (c) .
D) Graph (d) .
E) Both Graph (a) and Graph (d) .