In which state's metro rail network the DRDO has established the bio-digester Mk-2 technology?

In which state's metro rail network the DRDO has established the bio-d

1.	In which state's metro rail network the DRDO has established the bio-digester Mk-2 technology?
A.	Maharashtra
B.	Bihar
C.	Goa
D.	Kerala
Answer» B. Bihar