Answer:
The demand curve should shift to the right, increasing the equilibrium price and the total quantity demanded.
Step-by-step explanation:
When the demand curve shifts to the right, that means that the total demand will increase and the market price of the product or service will also increase at every level. The demand curve shifts to the right when consumers' income rises, the price of substitute goods rises, the price of complementary goods or services decrease, or the demand for complementary goods or services increases.
In this case the demand of a complementary good will decrease, since a song will be downloaded for free with the purchase of the book.