We had also considered that but Hard Palate is not specified. Though the postero lateral slopes of residual alveolar ridges are primary stress bearers, we followed our reference book Dental Pulse for answer. Thank you for bringing this out. The answer is dubious. But, let's hope in upcoming exams, the options will be more straightforward.
But according to BOUCHER palate is the primary stress bearing area while alveolar ridge is mentioned as secondary stress bearing area. Btw thanks for your valuable response.