For each of the diagrams in (add fig) write down the computational cost in terms of the number of occupied \( A \) and the number of unoccupied \( n_u \) orbitals.
The cost is \( A^2 n_u^2 \), \( A^2 n_u^3 \), \( A^3 n_u^2 \), \( A^2 n_u^4 \), \( A^4 n_u^2 \), \( A^3 n_u^3 \), \( A^4 n_u^4 \), \( A^4 n_u^4 \), \( A^4 n_u^4 \), and \( A^4 n_u^4 \) for the respective diagrams.