In order to protect the computer from virus attack, researchers developed anti-virus, anti-virus detection program, the former can make the program run from virus attack, the latter can quickly detect the virus may exist in the computer, a computer is installed with a, B, C three programs, known: (1) program A can kill all known viruses.(2) if program B cannot protect against known virus No. 1, program C cannot kill the virus.(3) Only if program C can protect against known virus No. 1, the computer can kill all known viruses.(4) Only if program A is started, can program C be started.
Based on the above information, which of the following can be concluded?
Only when the b program is started, can the first virus be defended and killed