Final answer:
The refusal based on religion and gender may be seen as discriminatory under the 1968 Civil Rights Act despite the seller claiming exemption, potentially violating the Act due to the public nature of the advertisement stating such preferences.
Step-by-step explanation:
The question revolves around an instance of possible housing discrimination described in an advertisement. The seller stated a preference for cash buyers who are female and of the Catholic religion, and subsequently refused an offer from a male Presbyterian. Under the 1968 Civil Rights Act, specifically the Fair Housing Act, this could be considered discriminatory as it refuses to sell property based on religion and gender. The owner of the house may claim exemption as a private seller, but if this refusal is based on discriminatory practices mentioned in the advertisement, the seller could be seen as violating the 1968 Act. This is particularly salient given the prior context of historically discriminatory practices in housing which the Civil Rights Act sought to remedy.