When Economists Say That the Demand for a Product Has

When economists say that the demand for a product has increased, they mean that

A) consumers are willing and able to purchase more at any given price.
B) the demand curve has shifted to the left.
C) the product has become more scarce and consumers therefore want it more.
D) consumers would be willing and able to pay less to receive the same quantity.
E) the price has decreased and consumers will therefore purchase more of the product.