Question: What is the date of death of Robert B. Claytor's mother?
Sentence (from "Robert B. Claytor"): He was the son of W. Graham Claytor (1886-1971), who as vice president of Appalachian Power Company supervised construction of the dam and creation of a 4,500 acre (18 km²), 21 mile (34 km) long lake on the New River at Claytor Lake State Park in Virginia, and of Gertrude Harris Boatwright Claytor, a poet.
Relevant evidence: Yes