Assertion : Cuprous salts are diamagnetic in nature.
Reason : `Cu^(+)` ion has filled 3d-orbitals.
A. If both assertion and reason are correct and reason is correct explanation for assertion.
B. If both assertion and reason are correct but reason is not correct not correct explanation for assertion.
C. If assertion is correct but reason is incorrect.
D. If both assertion and reason are incorrect.