Court gives considerable deference to an agency's interpretation of its own regulations,and construe the provisions of the relevant regulations and statutes to have cohesive meaning. It looks first to the intent of Congress as expressed in the statutory language, and, if silent or ambiguous, secondly to whether the administrative interpretation is a "sufficiently rational [choice] to preclude a court from substituting its judgment for that of the [agency]." The validity of a regulation so promulgated will be upheld as long as it is reasonably related to the language or purpose of the Act. Court upholds validity of SSI regulation that eligible individual married to eligible spouse continues to be treated as member of an eligible couple for first six months of separation.