Price elasticity of demand is calculated as the percentage change in the quantity demanded of the good divided by the percentage of change in the price of that good. The formula would be this; Price elasticity demand = Percentage change in quantity demanded / Percentage change in price. In our example, the price of this phone rises from 1500 TL to 1650 TL; therefore; the percentage of change is 10 % (150 / 1500 = 0.1 = 10 %). On the other hand, the quantity demanded decreases from 10.000 to 8.700; therefore, the percentage of this change is 13 % (1.300 / 10.000 = 0.13 = 13 %). When we 10 % is divided by 13 %, we can reach the price elasticity of demand as 1.3. The correct answer is C.