Ali sells burgers at an outdoor stand. There are several other burger stands in vicinity. All the burger seller are price takers. Which of the following statement is true about the demand for Ali's burger? a. Demand for Ali's burger is perfectly inelastic. b. Demand for Ali's burger is perfectly elastic. c. Demand for Ali's burger can be represented as a vertical line. d. Demand for Ali's burger can be represented as a downward sloping line