6. Using graphs and words, please explain whether each of the following events, a. through d. represents (1) a shift in the demand curve or a movement along the demand curve and WHY. Please make sure to explain that if there is a shift in the demand curve, the demand curve for that item shifts to the right or to the left from DI to D2. If there is a movement along the demand curve, please make sure you say that the price of the product rises or falls and the quantity demanded for the product falls or rises. a. A store owner finds that customers are willing to pay more for umbrellas on rainy days. b. When XYZ Telecom, a long distance telephone provider, offered reduced rates on weekends, its volume of weekend calling increased sharply. c. People buy more long-stem roses the week of Valentine's Day, even though the prices are higher than at other times during the year. d. The sharp rise in the price of gasoline leads many commuters to join carpools in order to reduce their gasoline purchases