Miguel’s big graduation party had been planned for weeks. His best friend approached him the day before the party and told him, "I won’t be able to make it to your party because something came up." Miguel was shocked. He felt that his best friend was either in big trouble over something or that they weren’t really friends after all. What kind of relationship rule was Miguel following?
a. constitutive
b. regulative
c. arbitrary
d. concrete
e. contextual