(a) In general. Except as provided in paragraph (b) of this section, part I, subchapter T, chapter 1 of the Code, applies to any corporation operating on a cooperative basis and allocating amounts to patrons on the basis of the business done with or for such patrons.

(b) Exceptions. Part I of such subchapter T does not apply to:

(1) Any organization which is exempt from income taxes under chapter 1 of the Code (other than an exempt farmers' cooperative described in section 521);

(2) Any organization which is subject to the provisions of part II (section 591 and following), subchapter H, chapter 1 of the Code (relating to mutual savings banks, etc.);

(3) Any organization which is subject to the provisions of subchapter L (section 801 and following), chapter 1 of the Code (relating to insurance companies); or

(4) Any organization which is engaged in generating, transmitting, or otherwise furnishing electric energy, or which provides telephone service, to persons in rural areas. The terms rural areas and telephone service shall have the meaning assigned to them in section 5 of the Rural Electrification Act of 1936, as amended (7 U.S.C. 924).