Assertion : Cr(VI) in the form of dichromate in acidic medium is a strong oxidising agent where `MoO_3 and WO_3` are not.
Reason: In d-block elements higher oxidation states are favoured by heavier members.
A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true and reason not is the correct explanation of assertion.
C. If assertion is trun but reason is false.
D. If both assertion and reason are false.