Concept:A rightward shift of the demand curve means that at every given price, consumers wish to buy a larger quantity of the good.
Explanation:A change in any non-price determinant of demand causes the whole demand curve to shift.
An increase in the income of the consumer raises purchasing power.
For normal goods, higher income leads to higher demand at each price.
Therefore, the entire demand curve shifts to the right.
Option A, a reduction in population, reduces the number of buyers and shifts demand to the left.
Option C, availability of close substitutes, gives consumers alternatives, which usually reduces the demand for the original good.
Option D, a decrease in the price of the goods, causes a movement along the same demand curve, not a shift of the curve.
Hence, the correct choice is the increase in consumer income.
Answer:B. An increase in the income of the consumer