Other Things Constant, an Increase in Households' Willingness to Save

Other things constant, an increase in households' willingness to save more at every level of income will cause:

A) the consumption function to become flatter because the MPC rises.
B) the consumption function to make a downward parallel shift.
C) the consumption function to remain stationary but the saving function to shift upward.
D) the consumption function to become steeper because the MPC declines.