c. When run with four processes (mpirun -n 4 ./a.out), this program freezes and does not produce any output. Why does it freeze, and how can you fix the bug? [4 pts] #include #include #include int main(int argc, char **argv) { MPI_Init(&argc, &argv); int rank, comm sz; MPI Comm rank (MPI COMM WORLD, &rank); MPI_Comm_size (MPI_COMM WORLD, &comm_sz); int round = 0; int neighbor = rank + 1 + (rank % 2 * -2); for (round = 0; round