Question: What is the date of birth of Bhanurangsi Savangwongse's mother?
Sentence (from "Bhanurangsi Savangwongse"): Although the Prince held a number of posts in the government of his elder brother, King Chulalongkorn, including the post of Commander-in-Chief of the Royal Siamese Army, he is best remembered as the founder of the Thai postal service.
Relevant evidence: No