Which of the following statements in relation to the hydrogen atom is correct?

1. A
   $3s$ orbital is lower in energy than $3p$ orbital
2. B
   $3p$ orbital is lower in energy than $3d$ orbital
3. C
   $3s$ and $3p$ orbitals are of lower energy than $3d$ orbital
4. D
   $3s,3p$ and $3d$ orbitals all have the same energy