What is the correct method for adjusting an existing approval policy that is assigned?

What is the correct method for adjusting an existing approval policy that is assigned?
A . Edit the existing policy and update the policy version number.
B . Copy the policy, edit the copy, and assign the new copy of the policy.
C . Create a new policy, delete the old policy, then assign the new policy.
D . Export the policy, edit in an XML editor, and import the policy.

Answer: B