Which of These Statements Describes Active Hyperaemia

Which of these statements describes active hyperaemia

A) arteriolar dilation that occurs within a tissue in response to local chemical changes that accompany increased metabolic activity of that tissue
B) local arteriolar mechanisms that are aimed at keeping tissue blood flow constant in spite of wide deviations in mean arterial driving pressure
C) the increase in blood flow to a tissue that occurs after removal of an occlusion of that tissue's blood supply
D) important in maintaining an adequate pressure head to drive blood forward into a tissue