Question: Who is the game designer born in 1950 who is best known for his work on materials for the "Dungeons & Drangon fantasy role-playing game?
Sentence (from "Dungeons &amp; Dragons Immortals Rules"): Dungeons & Dragons Immortals Rules, written by Frank Mentzer, is a boxed set for the "Dungeons & Dragons" ("D&D") fantasy role-playing game first published by TSR in 1986 as an expansion to the "Basic Set".
Relevant evidence: Yes