Market demand is the sum of all the quantities of a product demanded per period by all the buyers in the market. The market demand curve is found by adding horizontally the individual demand curves at all prices. Because there are hypothetically only four people in our market, we can reach the market demand by adding each individuals demanded quantity of soft drinks. That is, when drinks are 3 TL, 17 bottles of drink are demanded in total (5+2+6+4= 17). When they are 2,5 TL, 29 bottles of drink are demanded in total (8+3+13+5= 29). When they are 2 TL, 39 bottles are demanded in total (11+5+15+8= 29). When they are 1,5 TL, 52 bottles are demanded in total (14+6+20+12= 52). The correct answer is D.