"currently which hepatitis virus has more number of antivirals ? "
Hepatitis B.
There's only one thing used to treat Hepatitis C.....Peg interferon/Ribavirin
"Which hepatitis virus B or C cause cirrhosis earliest, if one is not on treatment ? "
If you have Hepatitis C....
About 20% of people develop cirrhosis after being infected for 20 years.....30% after being infected 30 years.....40% after being infected 40 years....on and on....
I think for Hepatitis B is more difficult to tell because Hep B can become inactive for a long time...and during that time it doesn't cause liver damage. And some people may clear it on their own and become immune to it.
Based on the fact that Hepatitis C is the main cause for liver transplants, I'm going to guess that it takes less time for Hep C to cause cirrhosis.