There is created in each community (as defined in § 4501 of this title) a public body corporate and politic, to be known as the “slum clearance and redevelopment authority” of the community. Such authority shall not transact any business or exercise its powers under this chapter until or unless the governing body shall approve (by resolution, as provided in this chapter) the exercise in such community of the powers, functions and duties of an authority under this chapter. If it deems such action to be in the public interest, the governing body may, instead of such resolution, adopt a resolution approving the exercise of such powers, functions and duties by the community itself or by a housing authority, and in such event, the community or housing authority, as the case may be, shall be vested with all the powers, functions, rights, duties and privileges of a slum clearance and redevelopment authority under this chapter.