What does 'no shift' in a demand curve mean?

A 'no shift' in a demand curve indicates that the demand for a good remains the same in response to a change in price, meaning that no external factors are influencing the market dynamics of that good. This scenario typically implies that while the quantity demanded may increase or decrease as the price changes, the overall demand curve—representing the relationship between price and quantity demanded at every price level—stays in its original position. Thus, if there are no external shocks or changes in consumer preferences or income, the demand curve will not shift to the left or right.

In contrast, the other options suggest situations that would typically cause changes in demand or market behavior. An increase in supply would shift the supply curve, affecting market equilibrium, while changing prices generally cause movements along the existing demand curve rather than a shift of the curve itself. Lastly, market forces at equilibrium represent a state where supply and demand are balanced, but this doesn’t directly relate to the absence of a shift in the demand curve.