Both A) & D) are correct.
Approval from the Irrevocable beneficiary is required to make changes; and the beneficiary becomes the owner of the policy.
Good question, and the distinction matters on the exam. A is the only correct answer. Naming an irrevocable beneficiary does not transfer ownership. The policyowner keeps the policy, pays the premiums and holds the ownership rights; what changes is that the owner can no longer change the beneficiary, assign the policy, or take a loan or surrender that cuts into the death benefit without that beneficiary's written consent. The beneficiary gets a vested interest in the proceeds, not the policy itself. If ownership actually passed, the exam would call that an absolute assignment or a transfer of ownership, which is a separate action.