With no explanation, label text_A→text_B with either "DON'T KNOW", "NO" or "YES".
text_A: After their marriage, Chifley's father-in-law gave the couple a house on Busby Street, Bathurst, which they would occupy for the rest of their respective lives. It is now listed on the New South Wales State Heritage Register as "Ben Chifley's House", and has operated as a house museum since 1973. Chifley and his wife had no children after their first son in 1913. She suffered a "serious health problem", probably a miscarriage, in about 1915, and later developed chronic back pain that restricted her mobility. The couple lived mostly separate lives, initially because of her husband's work on the railways and later because of his political career. She rarely travelled outside Bathurst and never lived in Canberra, even while her husband was prime minister. She usually visited the city for only special occasions. Her health prevented from campaigning for her husband, and she was known to have little interest in politics. Nonetheless, the couple "seemingly enjoyed a close and caring relationship throughout his life". She survived her husband by 11 years, dying in 1962.
text_B: Although the cause of Mrs. Chifley's health problems is assumed to be a miscarriage, is it possible that some other factor was to blame, and which had rendered her infertile before 1915?
NO.