This problem is actually very complex, and many conditions are uncertain.
First of all, it is necessary to confirm whether the declared patented technology of Q has been disclosed by the State Intellectual Property Office. It is disclosed that the above three technical features are all existing technologies and can be used to judge novelty and creativity. If the application is declared first and disclosed later, only the novelty can be judged. The criteria for judging novelty and inventiveness are determined based on the Patent Law, Implementing Regulations and Examination Guidelines.
It also depends on whether you want to apply for an invention patent or a utility model patent. Practical applications do not undergo strict substantive review and are easy to authorize. Of course, authorization is one thing, but whether it can be protected is another.
Invention patent authorization must meet three characteristics: novelty, creativity and practicality. If Q patent document is used as a comparative document to judge its creativity, apply for a patent of B or C alone or apply for a patent of B+C. If one or two of the elements are omitted, all the original functions will still be maintained or it will bring surprises. If the technical effect is less than the original, it will be creative.
It is best to analyze specific issues in detail.