This is a two part question, I need to know where to draw an arrow and also the multiple choice question below

The figure shows the demand curve for sundaes. Price (dollars per sundae) O 10T Suppose that the price of a sundae falls but all other influences on buyers' plans remain the same. Show the effect in the graph. Draw either an arrow on the demand curve showing the direction of change or a new demand curve. . . . If the price of a sundae falls, a the demand curve occurs. If any factor that influences buying plans other than the price changes, then a the demand curve occurs. O A. leftward shift of; movement up along D O B. rightward shift of; movement down along O C. movement down along; shift of 10 20 30 40 50 O D. movement up along; shift of Quantity (sundaes per day)