Which of the following will cause the demand curve to shift? A. a change in the cost of raw materials B. more firms in the market C. newer technology and improved productivity D. a change in consumer income

D. a change in consumer income

Explanation:

There are two main reason for shift in demand curve left or right in addition to price:

Change in consumer income. Change in preference.

Consumer income or earning affect the demand curve as according income of consumer, thier preference and priority changes. Example: Daily wages labor may have very less demand for Domino's Pizza or starbucks coffee, however, manager of any MNC may have higher demand for Domino's Pizza or starbuck coffee.