执行下面 C++ 代码可以找出千位与个位的和恰好等于中间两位的四位数，横线处应该填入（ ）。
int count = 0;
int a, bc, d, tmp;
for (int i = 1000; i <= 9999; i++) {
a = (tmp = i) / 1000;
____________
bc = tmp / 10;
d = tmp - bc * 10;
if (a + d == bc) {
count++;
}
}
cout << count;
- A.
tmp = i / 10; - B.
tmp = i % 100; - C.
tmp -= a * 1000; - D.
tmp = i - i%1000;