South Korean B-12 is arguably the most trustworthy for pharma grade, better than compounded in the US and more trustworthy for sterility, endos, etc. than the small Indian pharma companies that provide B-12 for export.
Ocean Pharmaceutical (a small company in India) is becoming popular for testing well for BAC (including for sterility and endos), so their B12 may be trustworthy for sterility. They at least sell cyanocobalamin ampules. But the testing needs to be repeated, and the B12 isn't being tested at all. So I would still be more comfortable with something from Korea.
But the research shows that the oral supplements can be just as good as B12 shots in the long term. The shots are more for acute/severe cases. At least in the US, most docs will order B12 bloodwork upon request.