Step 1: Understand the scenario.
A leftward shift of demand means that at any price level, consumers want to buy less than before. This creates imbalance in the market.
Step 2: Arrange logically.
- (A) At any given price, demand is less. → First effect of demand curve shifting left.
- (C) Some producers will decrease the prices of commodity. → To clear excess stock, suppliers reduce prices.
- (B) Excess supply will be there. → As demand is less, supply exceeds demand at old price.
- (D) At new equilibrium, quantity and price will be less. → Market reaches new equilibrium with lower price and lower quantity.
Step 3: Verify order.
Thus the correct logical sequence is: (A) → (C) → (B) → (D).
Final Answer:
\[
\boxed{(A), (C), (B), (D)}
\]