1066- Who had the best Claim?

I believe that Duke William had the strongest claim. Harold had taken an oath to help Duke William become the king of England after Edward the Confessor died. In the Medieval times, being called an oath breaker was a minor moral sin which was frowned upon. Duke William also claimed that in 1051, when he visited Edward, Edward chose him as his successor. The leader of Norway, Harald Hardrada, also had a claim for the throne. Harald Hardrada's claim was that one of Harald's ancestors, King Cnut was king of England before. I believe that William had the best claim because Harold Godwinson had taken an oath to help William become the next king of England, and Hardrada's claim was not direct enough because it was one of his ancestors that was the king of England.