You have to choose a very specific target group here and do some research because what people want to wear is dependent on how they make choices on what they wear, the technological augmentation and interactions they prefer and also what sports means to them. If you focus on sports. You have to get the context clear first. If I look at people in my neighborhood, there are a lot of runners and some professional soccer players as well, almost nobody runs with headphones and if they do, it's the over the ear design which is quite easy to wear too and actually associated with sports. I like them, they look professional like you are dedicated. My own preference as a runner for wireless headphones is to leave all wires at home, also do the charging at home, and induction would be great just like you can do with smartwatches. It doesn't even need a terminal penetrating a coil. I would prefer to have each headphone completely wireless, hook to the ear, with enough battery built in. Even if it would look a bit clunky I would prefer that over anything that looks wired.
1/B is my preference so far. I'm sure in the future all electronics for a music player can be integrated into the device.