Question: Who is the sibling-in-law of Susan Mary Alsop?
Sentence (from "Susan Mary Alsop"): The wife of columnist Joseph Alsop and a descendant of founding father John Jay, her Georgetown home hosted dignitaries and publishers during the 1960s and 70s ranging from John F. Kennedy, Phil and Katharine Graham, and Isaiah Berlin, earning her the nickname "the grand dame of Washington society."
Relevant evidence: Yes