Hi,
after reading Rule 602, I am unsure how to handle the following situations. My actors are Experiment Kraj (the first ability) and any kind of Rootwalla (the restriction).

Scenario A: I activate Rootwalla, then put a +1/+1 counter on it. Can I activate that ability on Experiment Kraj this turn?

Scenario B: I put a +1/+1 counter on Rootwalla, then activate that ability on Experiment Kraj. Can I activate Rootwalla this turn?

Scenario C: I put a +1/+1 counter on Rootwalla, then activate that ability on Experiment Kraj, then remove the counter, then put there another counter. Can I activate Rootwalla? Can I activate that ability on Experiment Kraj?

Thanks a lot!