Answer:
The correct answer is option b.
Step-by-step explanation:
When GM advertises its cars, it's trying to increase the demand for its cars.
An increase in the demand for a product is indicated by a rightward shift in its demand curve.
So advertising indicates that the company is trying to shift it's demand curve to the right.
A rightward shift in demand is caused by change in other factors while price of the product remains constant.