A JavaFX Button’s event handler receives a(n) ________, which indicates that the Button was clicked.

A university identifies a class by subject area and course number. The university has classes Math 101, Math 102, and MIS 101. It takes both subject and course number to identify a single course. The combination of the two fields is called a ________ key

A) foreign B) natural primary C) composite D) primary

Finding ________ values and knowing what to do with them remains one of the challenges of good database design.

Fill in the blank(s) with the appropriate word(s).