Block - Charge (consider this)

[footlocker]

Something similar happened in my game last night and it begged this question:

If player A has the ball and is driving toward the hoop and the defensive player B is standing completely still.

Here is the catch. Player B has his back to player A and has never established legal guarding position. Is it a charge because B has his right to a space on the floor? Is it a block because B never had legal guarding position?

I don’t have my rule book with me so if someone could quote rules that would be great.