Assertion : Benzene forms benzene sulphonic acid with fuming `H_2SO_4` at high temperature .
Reason : The attacking species is `SO_3`
A. If both assertion and reason are true and the reason is the correct explanation of the assertion
B. If both assertion and reason are true but reason is not the correct explanation of the assertion
C. if assertion is true but reason is false
D. If assertion and reason both are false