Which of the Following Statements Concerning Graded Streams Is NOT

Which of the following statements concerning graded streams is NOT true?

A) A graded stream responds instantaneously to any change in sediment load or discharge in such a way as to establish a new graded state.
B) After a sudden decrease in sediment load, the gradient decreases, as does stream velocity.
C) The equilibrium of a graded stream is temporary and lasts only until the next change in its environment.
D) After a sudden increase in sediment load, the gradient increases, as does stream velocity.