The University of Dover and Dover University are bitter rivals. They compete in everything from sports to academics. The schools, because of shrinking enrollment, make an agreement to give all incoming students free tuition for one semester before raising the existing rates the following semester. This action would be considered:

A. A horizontal agreement in violation of the Sherman Act. B. A vertical agreement in violation of the Sherman Act. C. A tying agreement in violation of the Clayton Act. D. A reciprocal dealing agreement violating the Clayton Act.