Organizations set up their bodies and organs in line with their purposes, goals, principles and even number of members. The duly take into account regional and international climate, as well. Organization have, or create in the course of time, bodies deemed necessary for the fulfilment of organizational purposes and functions. Yet they all, almost as a rule, basically have three main bodies: Secretariat, plenary assemble and specially authorised body.

Secretariat is the body that in fact both supplies and represents the legal personality of the organization. It is the only body that is not composed of the representatives of the member States but rather employs officers working for, and accountable to, the organization itself.

Plenary assemble is the sole body that contains the governmental representatives of all member States. It is usually equipped with general powers and authorities regarding the structure and operation of the organization. It approves the budget, admits new members, amends the statute and so on. It ordinarily meets sparsely, say annually or even once in two years, to discuss, consult and negotiate general issues on its agenda.

Almost all organizations have a core specially authorised body which is usually called council or board and is equipped with special powers. Unlike the assembly, it has a limited number of members. These members are either elected by the plenary assembly for a certain period of time according to certain criteria or envisaged as permanent members in the statute of the organization.

The correct answer is B. Secretariat is the body that in fact both supplies and represents the legal personality of the organization. Specially authorised body is equipped with special powers. As can be understood from the information given, specially authorised body is usually called council or board.