Which one of the following statements best describes the most important feature of a support trust?

A) It provides for the trustee to take over management of the grantor's assets only upon the occurrence or nonoccurrence of certain specified events.

B) It provides that the trustee shall distribute only so much of the income or principal as the trustee deems necessary for the support of a named beneficiary.

C) It is created by the terms of a will and therefore does not become effective until death.

D) Trust assets must revert to the grantor.