Concept:An exceptional demand curve goes against the normal law of demand by showing higher quantity demanded as price rises.
Explanation:This usually happens when consumers expect future prices to increase.
They buy more at the current higher price to avoid paying even higher prices later.
This makes the demand curve slope upward instead of downward.
A change in taste only shifts the demand curve and does not create an exceptional shape.
An increase in population also shifts demand without breaking the law of demand.
An increase in raw material price affects supply, not the nature of the demand curve.
Answer:D. Expectation of future price increase.