下列程序的运行结果是#include int main (void){ int a, b, c; a = 20; b = 30; c = 10; if (a < b)a = b; if (a >= b)b = c; c = a; printf("a=%d, b=%d, c=%d", a, b, c); return 0;} A. a=20, b=10, c=20 B. a=30, b=10, c=20 C. a=30, b=10, c=30 D. a=20, b=10, c=30