Demand & Supply

an excess quantity demanded means the quantity supply can not satisfy all the quantity demand
since Qd is larger than Qs, scarcity exists and the goods are economic goods
there is a problem of resources allocation
therefore, choice, price competition and non-price competition are needed

b. put upward pressure on price
means the price competition, so it is the right answer.

如果用Economics既定義去講,上面果位仁兄已經講得好清楚.

如果用市井D或者common sense D既講法去講,就係excess quantity demand即係有人想買某樣野但係買唔到,咁D商家見到咁梗係可以吊高黎賣都唔驚,因為有D人當想要某樣野既時候俾貴D都唔介意嘛.

所以大體上,個價格係會有向上既壓力,所以B岩啦.至於點解D唔岩,因為如果要supply上升,即係要D商家無論售價係幾多都好都要生產多D.所以而家只不過係quantity demand excess左,根本唔需要考慮到咁大規模咁去提高生產,所以答案唔包D,即係只需選B.