Assertion (A): Parliament or a State Legislature should keep within the domain assigned to it and one should not tresspass into the domain reserved for the others.
Reasons (R): Legislation will be invalid even if it incidentally trenches or encroaches on matters which have been assigned to another Legislature

A. Both A and R are true and R is correct explanation of A

B. Both A and R are true but R is not correct explanation of A

C. A is true but R is false

D. A is false but R is true

Answer: Option B