$2.$ From the statement $$Lincoln is the $16$th US president$,$ we can come up with the following designs. Which one is most appropriate? $(4$ points$)$:

a$.$ Two independent Classes: Lincon and President.

b$.$ Two Classes: Lincon and President, with Lincon subclass of President.

c$.$ A class President, with Lincon being an object of the class President.

d$.$ None of the above.