Which of the Following Would Be a Source of Vertical

Which of the following would be a source of vertical conflict?

A) if Foot Locker decided to open a retail outlet next to a Nike store in a mall.
B) if a restaurant served both Coke and Pepsi to its patrons.
C) if Ansible Technologies Ltd sold its portable planetariums to both colleges and high schools.
D) if a Mcdonald's franchise wanted to purchase its produce through its own vendor.
E) if Long John Silver's decided to serve grilled burgers in addition to fish.