A ${20}^{\text{'}\text{'}}20"$ square tied column is reinforced with $(12)$ #$9$ bars on two faces$-(6)$ bars on each face. Use the interaction diagram below to determine if the column can handle loads of $P_u=840k$ and $M_u=400k-ft.P_c=5,000$psi and $f_y=60$ksi. Plot the load and moment on the diagram, identify which curve should be used, and state whether the column is safe or not.