How the revelation of the fact that junk-foods might be injurious to health can affect the Demand Curve of junk-foods.

Leftward shift in demand curve of junk-foods.

The correct answer is Option (4) → Leftward shift in demand curve of junk-foods.

If it is revealed that junk-foods might be injurious to health, consumers are likely to reduce their demand for such products due to health concerns. This change in consumer preference causes the entire demand curve to shift to the left, indicating a decrease in demand at every price level. This is not a movement along the curve (which would be caused by a change in price), but a shift in the demand curve due to a change in non-price factors (like awareness of health risks).