Here is a single or multi-choice question: Who invented the Moog Synthesizer ?

Would the answer to this question be an entity, an abbreviation, a description, a human, a location, or a numeric value?

OPTIONS:
 (a). description;
 (b). entity;
 (c). abbreviation;
 (d). human;
 (e). numeric;
 (f). location;
(d).