Source MasterExam CD included with K&B book. Which statement(s) are true? (Choose all that apply.)
A: is-a relationships always rely on inheritance.
B: is-a relationships always rely on instance variables.
C: is-a relationships always require at least two class types.
D: is-a relationships always rely on
polymorphism.
E: is-a relationships are always tightly coupled.
Why the correct answers accordingly to masterexam are A C and D? I'd rather say that all the options are false. Comments?
A: false because they rely on inheritance OR (interface) implementation.
B: false because inheritance is independent of the existence of instance variables. (original explanation)
C: false because they require at least two types, not necessarily class types (interface A {} class B implements A { } // an instance of B is-a A)
D: not sure but I'd say false. Isn't polymorphism a "feature" that rely on inheritance? (No inheritance -> no polymorphism)
E: false because coupling is not used to evaluate classes within the same inheritance tree. (original explanation)
Thanks