Immanuel Kant -Having Shown That Metaphysics Is Unproved and Speculative at Best,Kant

Immanuel Kant
-Having shown that metaphysics is unproved and speculative at best,Kant goes on to argue that

A) we ought not waste time with that of which we know nothing.
B) we ought to study metaphysics as a science because it asks good questions.
C) rather than studying speculative metaphysics to learn about sense perceptions,we ought to study sense perceptions in order to learn about metaphysics.
D) we should use common sense in regards to metaphysics.