In the New Keynesian Expression for the Price Level, C

In the new Keynesian expression for the price level, c represents

A) the fraction of firms in the economy with sticky prices.
B) the marginal propensity to consume.
C) the responsiveness of the price level to differences between actual aggregate output and full-employment aggregate output.
D) the responsiveness of aggregate output to the difference between the actual price level and the expected price level.