I was told that IS-A means, we should use either extends or implements Runnable.
--> Please cross check
This is seriously going off the track!..
Consider following points:
1) Since its an objective question, which has various options and Dog IS-A Animal is fine. Only other option that can be selected is Dog IS-A Dog, all other options are 100% wrong.
2) However please note a code like
will not compile, saying Cyclic Dependency.
3) benefit of doubt to Dog IS-A Dog since you can cast a Dog instance to Dog Type.