Final answer:
A durable power of attorney may be terminated by revocation from a competent principal or upon their death. It is not irrevocable and maintains the principal's control until death.
Step-by-step explanation:
A durable power of attorney may be terminated by c. revocation by a competent principal or by the death of the principal. While 'durable' suggests a level of permanence, it does not imply that it is irrevocable under all circumstances. A durable power of attorney remains effective even if the principal becomes incapacitated, but it can still be revoked by the principal if they are deemed competent. Option c. is correct.
Additionally, just like any power of attorney, it is terminated upon the death of the principal. This allows the principal to maintain control over the power of attorney while they are capable of making decisions.