A factor that most directly affects the demand for automobiles is

the individual tastes and preferences of buyers.

the cost of raw materials and natural resources.

the availability of workers in automobile factories.

a company's ability to respond to buyers' interest.

Consumer demand changes over time based on many factors. A factor that most directly affects the demand for automobiles is a company's ability to respond to buyers' interest. One of the buyers interests is the price. The price is the factor that most influences changes in consumer demand.

Pretty sure it's "A".