The correct answer is: "there will be an excess of demand, and price will increase to reestablish the market equilibrium"
If there is a sudden shock in the market of potatos which causes scarcity, the supply curve shifts to the left (as shown in the attached graph) and a new equilibrium point will be reached due to an increase in the price charged for potatoes, while the amount exchanged has decreased. The increase in price has reduced the amount of consumers who are willing to purchase potatoes at the more expensive price, and the price will keep on rising until the quantity demanded matches the quantity supplied after the shock.