Question: Who is Cao Xun's paternal grandmother?
Sentence (from "Cao Rui"): Based on conflicting accounts of his age, Pei Songzhi calculated that, in order to be Cao Pi's son, Cao Rui could not have been 36 (by East Asian age reckoning) when he died as recorded, so the recorded age was in error; Lu Bi and Mou Guangsheng argued instead that Cao Rui was Yuan Xi's son.
Relevant evidence: No