对于ROOT::Math::beta_pdf,其参数为double beta_pdf(double x, double a, double b); 用下列那种方式可以组装成RooFit能识别类型： A、 RooAbsReal *roof = bindFunction(“f”,ROOT::Math::beta_pdf,x,a,b); B、 RooAbsPdf *roof = bindFunction(“f”,ROOT::Math::beta_pdf,x,a,b); C、 RooAbsPdf *roof = bindPdf(“f”,ROOT::Math::beta_pdf,x,a,b); D、 RooAbsReal *roof = bindPdf(“f”,ROOT::Math::beta_pdf,x,a,b);