What is the correct order of energy of atomic orbitals in any given shell?

If the principal quantum number $n=6,$ the correct sequence of filling of electrons will be

Show the distribution of electrons in an oxygen atom (atomic number $8$) using an orbital diagram.

Consider the following pairs of electrons:
$(A)$ $(a)$ $n=3, l=1, m_{l}=1, m_{s}=+\frac{1}{2}$
$(b)$ $n=3, l=2, m_{l}=1, m_{s}=+\frac{1}{2}$
$(B)$ $(a)$ $n=3, l=2, m_{l}=-2, m_{s}=-\frac{1}{2}$
$(b)$ $n=3, l=2, m_{l}=-1, m_{s}=-\frac{1}{2}$
$(C)$ $(a)$ $n=4, l=2, m_{l}=2, m_{s}=+\frac{1}{2}$
$(b)$ $n=3, l=2, m_{l}=2, m_{s}=+\frac{1}{2}$
The pair$(s)$ of electrons present in degenerate orbitals is/are...... .

Which electronic configuration does not follow the $(n + l)$ rule?

Correct set of four quantum numbers for the outermost electron of rubidium $(Z=37)$ is :