^{Let Aggregate Demand Be Summarized by Y = k}0

^{Let aggregate demand be summarized by Y = k}0 ^{+ k}1^{M - P) and aggregate}
Supply by P = P^{^}
^
+ cY - Y*) . All notation is standard but for , which here
Represents forecasted general prices. A change in the responsiveness of firms' prices to expectations is captured by a change in

A) only c.
B) ^{only k}1^.
C) ^{only k}0^.
D) ^{both k}0 ^{and k}1^.
E) none of the above.