Java*

what is the time complexity and space:

1A)int sum = 0;

for (int i = 0; i < n; i++)

for (int j = 0; j < n*n; j++) sum++;

B)int a = 0, b = 0;

for (i = 0; i < N; i++) {

a = a + rand();

}

for (j = 0; j < M; j++) {

b = b + rand();

}

C) for (int i = 0; i < n; i++){ for (int j = 0; j < n; j++){

C[i][j] = 0;

for (int k = 0; k < n; k++){ C[i][j] += A[i][k] * B[k][j];

}

}

}

D)for (int i = 0; i < n; i++){ for (int j = 0; j < i; j++){

A[i][j] = 0;

}

}

is this brackets symbol balanced:

{ [ ( ] ) }