have CyO Bc? please..

[B. Iyengar]

Hello all,
Can somebody please tell me if there is a stock available 
anywhere which is CyO,Bc? (Bc stands for Black cells).
Basically, a marked balancer that will be visible in live
larvae. I know CyO(y+) exists and I have used it, but 
I have to let go this for some artifacts associated with this
stock. Thanks very much for your time! Hope my luck is good!!
Bala
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