单项选择题
A.printf("x=%d\n",x); B.printf("x=%1d\n",x); C.printf("x=%8dL\n",x); D.printf("x=%LD\n",x);
A.3*x^n/(2*x-1) B.3*x**n/(2*x-1) C.3*pow(x,*(1/(2*x-1) ) D.3*pow(n,/(2*x-1)