The definition of A/B/C players is mostly subjective and dependent on the company as well.
An excellent Java developer can suck at a Python house and vice-versa (probably will suck less, but still).
But, the main definition of "A-Players" seems to be people that will overwork themselves for the company
And for these I say: yes, I'm not an A-Player, sorry...
I've yet to meet an excellent developer who was only excellent in his language of choice. In my experience at least, almost all of the talents that make an A player an A transcend whatever language they're using and has far more to do with their ability to reason and hold an entire system in their head.
It's really not even anything that consistent.
The definition of "A Players" is "whoever management is currently in love with."
Putting in long hours, doing incredibly vital work, but the brass doesn't get that funny feeling in their pants when they think about you? Then you're a B player at best and management has an infinite list of reasons why it's your fault that's the case.
It's utterly narcissistic ego-driven garbage.