Another vote for A
I also would prefer Solution A, for the same reasons mentioned above. One of the keys to fast text entry is to have to *think* as little as possible about the tool being used. If you have to think about the current state of the keyboard, it interferes with your stream-of-thought. Especially if you forget the current state and expect one response and get another, as anyone who's forgotten the state of their NumLock key on their PC keyboard should be able to attest to :).