Question: What was the name of a thoroughbred racehorse that won the 1889 Epsom Oaks and was owned by the Earl of Dunraven and Lord Randolph Churchill, a man who created the National Union of the Conservative Party?
Sentence (from "Dibidale"): After one minor win in two races as a two-year-old, she emerged as arguably the best filly of her generation in the following year.
Relevant evidence: No