The Airlines Sold Fewer Tickets to Business Travelers During the "Great

The airlines sold fewer tickets to business travelers during the "Great Recession" due to more companies using video conferencing software to save money. According to the five forces model, this type of threat is called the

A) level of rivalry among organizations in an industry.
B) potential for entry into an industry.
C) power of large suppliers.
D) power of large customers.
E) threat of substitute products.