Option 1 -> Price ceiling below equilibrium creates shortage where Qd > Qs.
Option 2 -> Excess supply occurs with price floor, not price ceiling.
Option 3 -> Incorrect calculation of the demand-supply gap at Rs 31.
Option 4 -> Excess supply contradicts price ceiling effects.
Hence, Excess demand of 68 units -> When a price ceiling of Rs 31 is imposed below the equilibrium price, quantity demanded exceeds quantity supplied at this price level. The difference between quantity demanded and quantity supplied at P = Rs 31 equals 68 units, creating a shortage in the market. This shortage occurs because at the artificially low price, consumers want to buy more than producers are willing to supply -> correct