Which the followings is$/$are true about behavioral state machine diagrams?

Consider the in$-$class example where classes Freshman, Sophomore, Junior, and Senior which were subclasses of the class Undergraduate. For this case, using subclasses instead of states is more reasonable.

Creating a behavioral state machine can help discover additional events for the functional model

An event is a relationship that represents the movement of an object from one state to another state.

The state of an object is defined by the number of its attributes

The state of an object is defined by the value of its attributes