Final answer:
The correct answer is c) Marquess, which is a noble title positioned between an earl and a duke, and is associated with the Marquess of Queensberry Rules in boxing.
Step-by-step explanation:
The title that fits both the clue of being above an earl yet below a duke and also referenced in the context of boxing rules is a Marquess. The term Marquess (or Marquis) is a noble rank in various European peerages, falling below a duke and above a count, or earl, in the British peerage system. Furthermore, the term is familiar to boxing enthusiasts due to the Marquess of Queensberry Rules, which are a set of standardized rules in the sport of boxing dating back to the 19th century.