I'll stick my neck out and say they both look like bad circuits. What are they supposed to be for?
In circuit B, R0 increases the loop gain so if some current is injected to start with, I would expect the current to increase and stay high after the external current injection is removed.
In circuit A, R1 decreases the loop gain below unity, so I would expect the current to reduce to zero when the external current injection is removed.
If no current is injected, I don't think circuit A will ever switch on by itself. Circuit B would probably start due to leakage current, but the current would quickly rise to a high (and badly defined) level.