All four listed personalities were indeed awarded the Bharat Ratna posthumously. However, given the multiple-choice format expecting a single correct answer, and assuming the question is from a period where only one of these individuals had received the award posthumously among the specific options listed, Dr. Ambedkar (awarded in 1990) is the most likely intended answer if the question predates the posthumous awards to Pt. Madan Mohan Malaviya (2015), Nana ji Deshmukh (2019), and Bhupen Hazarika (2019).