Sample rate. Audio files played back at the wrong sample rate will play back at the wrong speed and pitch.
The bit depth is a different animal. 🙂
Here's a good primer if you want to dig deeper: https://www.izotope.com/en/learn/digital-audio-basics-sample-rate-and-bit-depth.html
As for the bit rate, it's a parameter when you bounce an mp3 file, that affects the size and quality of the audio file, but not the tempo or pitch.