I protest the unrelated dual components of the question. And the lack of enough choices. And the inclusion of a fictional aircraft in the choices. But the P-47 is the obvious choice.
Well aaaactually its "Fw 190" and "Bf 109" (no hyphen in case you hadn't spotted). I'd also like to include the Hawker Tempest, Hawker Typhoon, P-51B, Me 262, CAC Boomerang, F4U, Spitfire XIV specifically, Hurricane IIc, P-40, Yak-3, F6F... the inclusion of these (and more...) types would make the poll a whole lot more interesting.
Because of all the books that say so. The only way anybody like me who "wasn't there" can know anything. I realize the Bf 109 was also known for its diving abilities, but it wasn't quite listed as an option, and the P-47 is reported to be the first aircraft to break the sound barrier in a dive. ("needs citation")
It was the first aircraft to encounter compressibility and have it widely reported, however given the time and date this happened it could very well the first aircraft to encounter compressibility;
"During a test flight in May 1941, USAAC Major Signa Gilkey managed to stay with a YP-38 in a compressibility lockup, riding it out until he recovered gradually using elevator trim."